pipeline corrosion in Alaska ? ?
pipeline corrosion in Alaska ? ?
(OP)
I wondered if anyone had heard what type of corrosion caused the problem on the pipeline.
I read one or two references to a smart pig having discovered corrosion, indicating it's internal, but given how news stories get screwed up, wondered if anyone had a link to reliable info.
This is outside my field. Is 30 years the life expectancy on above ground pipelines?
Dan
I read one or two references to a smart pig having discovered corrosion, indicating it's internal, but given how news stories get screwed up, wondered if anyone had a link to reliable info.
This is outside my field. Is 30 years the life expectancy on above ground pipelines?
Dan





RE: pipeline corrosion in Alaska ? ?
It seems that the pipeline steel, which was adequate for the orignal crude, could not stand up to the mixture of water, gas, and oil currently produced. Acidity and sulfur make the mixture much more corrosive. They tried using inhibitors but this could not reach the pipe wall because of the buldup, so corrosion went unchecked.
The life expectancy was apparently calculated to be finite but adequate. It seems, however, that it was incorrectly based on projected acceptable corrosion rates with the caveat that inhibitors could be used to compensate for errors or changes in the projected rate. The sludge defeated that option.
I am waiting to see if they use a weldable 13Cr plus Mo, Ni, Cu line pipe to replace this section. There are such alloys which would have essentially zero corrosion compared to carbon steel. Maybe it wouldn't pay since they need to continue to inhibit the for the rest of the line. One wonders how long the rest of the Alaska pipeline will last if this occurrence was a surprise. You can bet that new pipelines won't escape having to justify their use of finite-lived materials when dealing with corrosive crude.
I expect that the publicity of this Prudhoe Bay failure will cause some pipeline specifiers to get out their metallurgy books and see what one needs to obtain correct corrosion resistance. BP probably did what was right in the 1960's, but that won't work in the future.
Michael McGuire
http://stainlesssteelforengineers.blogspot.com/
RE: pipeline corrosion in Alaska ? ?
I'll wager that in the end we find out that cleaning, inspection and inhibition were all limited by buget constraints.
My guess is that they will go back with 2 1/2 Cr. It will have good resistance and survive a long time with very little care.
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RE: pipeline corrosion in Alaska ? ?
Michael McGuire
http://stainlesssteelforengineers.blogspot.com/
RE: pipeline corrosion in Alaska ? ?
The only 2205 that I know of is the transmition line.
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RE: pipeline corrosion in Alaska ? ?
RE: pipeline corrosion in Alaska ? ?
RE: pipeline corrosion in Alaska ? ?
http://www
There was a report on CNN that showed a section of pipe during a report on the problem that showed as section of pipe. The pipe showed 100% corrosion coverage with a surface morphology of sandpaper.
A later report from a reporter at the scene mention that bacteria was cause of the corrosion.
RE: pipeline corrosion in Alaska ? ?
RE: pipeline corrosion in Alaska ? ?
News articles have mentioned that BP tried boosting inhibitor (from 20 to 200 ppm?), but too little, too late -- and I don't see how inhibitors would help considering the buildup.
A section of the corroded pipe, after cleaning, is shown in the ABC News story:
h
RE: pipeline corrosion in Alaska ? ?
One problem is that they have no holding facility for the sludge that they push out of these lines. And the pipeline guys sure don't want it.
I wish that petrol products were a consumer commodity. If so then there would be less price swing and BP would stand to loose tens of millions due to lost capacity.
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RE: pipeline corrosion in Alaska ? ?
RE: pipeline corrosion in Alaska ? ?
RE: pipeline corrosion in Alaska ? ?
RE: pipeline corrosion in Alaska ? ?
This is a link to BP's Corrosion Management report for 2005 for Alaska to the Alaskan Department of Environmental Protection. 200 pages of a supposed comprehensive corrosion management. I wonder if they will ever be believed again!
Nigel Armstrong
Karachaganak Petroleum
Kazakhstan
RE: pipeline corrosion in Alaska ? ?
RE: pipeline corrosion in Alaska ? ?
According to the news story (by an AP writer) cited below, yes.
Bacteria can hitch a ride into the pipeline in the cold salt water that is sucked from the nearby Beaufort Sea and injected into the ground to coax the field's dwindling supply of oil up to the surface.
Oil, gas and water all exit the permafrost together and are separated out at flow stations scattered throughout the North Slope, the nation's most remote oil region. In addition to seawater, the fresh water and natural gas are pumped back down to help maintain the underground pressure that pushes the hot oil to wellheads, which from a distance resemble red Christmas trees.
Microbes can enter any groundwater that contacts air before flowing back into the layer of gravel and sandstone 9,000 feet beneath the spongy tundra.
More and more water has come up from the ground as production rates have fallen from a 1989 high of 1.5 million barrels per day to 400,000 barrels before the shutdown. The water was most likely siphoned off before oil reached the corroded section of pipeline, but BP is looking into the possibility that some got by, according to Copeland.
"As the field has declined the water sitting underneath the oil has increased," Copeland said. "The ratio of water to oil coming out of the ground is higher."
htt
RE: pipeline corrosion in Alaska ? ?
As I stated previously, it was well known in the early 1980's when sea water injection was introduced that the formation would be "poisoned" with introduction of SRB and H2S would be created. Unfortunately, MIC was not as well understood at that time.
RE: pipeline corrosion in Alaska ? ?
h
Nigel Armstrong
Karachaganak Petroleum
Kazakhstan
RE: pipeline corrosion in Alaska ? ?
rorschach hit the nail on the head. It could be a case of SRB (sulfate reducing bacteria) attack, Desulfovibrio desulfuricans. I have seen cases of this attack in oil well casings, sucker rods and some cooling water systems contaminated by small amounts of crude oil. It is seen as a a series of shiny concentric rings inside of pits on the metal surface of typically carbon steel and it's alloys. There are tests for the bacteria, biocide treatments and monitoring methods. I'm surprised that with all the new technology for monitoring pipelines that such an old villian was not detected if SRB attack is the case. It is also prevalent under many other conditions. There is much information on the internet on this subject.
RE: pipeline corrosion in Alaska ? ?
The problem is inertia., company's unwillness to change teh way that they do things. In other parts of the field BP was doing all of the correct stuff.
How often have we all sat in meetings and heard senior managers tell us that they won't spend the money until 'it becomes a real problem'. Short sighted planning and managment styles will not allow prevention to be seen as an investment, only as a cost.
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Rust never sleeps
Neither should your protection
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RE: pipeline corrosion in Alaska ? ?
I don't think we've heard the last major leak from the Oil & Gas industry and maybe not the last from BP, but I see IM as an increasing priority across the industry and you will definately see fewer than you would have without the changes in thinking.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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