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Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

(OP)
Onshore buried 36" Main Oil Line is submerged under water for around 16 km during winter seasons and high tide conditions. Access and maintenance of MOL is very difficult during such conditions.
Design Prussure = 120 barg
Design Temperature = 85 C
Material API 5L X 60
NPS = 36 "
Therefore, we are looking for rehabilitation options / possible engineering solutions. Any suggestions please.

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

Could be quite dangerous.
Is the pipe buried now, or exposed during low water? What type of soil? The same in the picture?
Does the pipeline have any concrete weight coating or set-on type, saddle weight blocks?

Screw Anchors may be the easiest solution at this point, otherwise you may be looking at building a dike and filling over the pipeline (rock armouring, gabion mattresses?) to keep the tide far away and possible future erosion well under control.
https://www.google.co.uk/search?q=pipeline+screw+a...


RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

Hussam,

This is more of a consultancy project, but to give you some (free) input, can you answer questions below.

Is pipeline buried?
If not or part, how much
If buried how deep?
what is the coating?
what is the field joint coating?
What is operating temperature?
What are your issues / problems? - Is it becoming damaged or exposed?
Do you have significant external or internal corrosion?
Has the line been internally inspected recently?
How old is it?
What was original wall thickness?
what is CP system? (sacrificial? / impressed current?)
Does it work?
Can you access outside of winter / high tide?

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

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

(OP)
The MOL was buried but now exposed/covered with water, it is the same one in the picture.
Unfortunately, The pipeline was designed without concrete coating or any measures towards such situation.

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

(OP)
Is pipeline buried? was buried but now exposed/covered with water
If not or part, how much The total length of MOL for rehabilitation 9.5 KM
If buried how deep? Was buried @ 1 meter
what is the coating? 3LPP
what is the field joint coating? hot shrink sleeves
What is operating temperature? 65 celsius
What are your issues / problems? - Is it becoming damaged or exposed? Pipeline shall be modified such that MOL can be easily accessed and maintained in all conditions. Plus Stability / Floatation / CP System / Coating.
Do you have significant external or internal corrosion? No available Info
Has the line been internally inspected recently? No available Info
How old is it? Around 5 Years
What was original wall thickness? 20.5 mm
what is CP system? (sacrificial? / impressed current?) impressed current
Does it work? Yes
Can you access outside of winter / high tide? Yes

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

You're lucky it's still there.
Even luckier that it's still in one piece.
Dike immediately to stop water washing across, if possible
Backfill and rip rap any severely washed out areas, block further water ingress channels.
Call your nearest pipeline engineering specialist contractor.


RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

Still not really sure what your issues are or what is actually feasible - it looks like there are lots of other pipelines in parallel across what lokos like a beach or very flat piece of land.

At 65C, your weak point is the hot shrink sleeves. Pretty soon your CP system will be flat out protecting those joints, but where you get shielding of water, especially if it's slightly salty, your line will just disintegrate in front of you. SO I think you have a mojor bob to dig all the joint sup and do something a lot better with the field joints- probably fusing the field joint to the PP coating is what you need.

Other than that why do you feel the need to easily access this line. If it's well built and cared for you don't need access and just bury it and if you need to weigh it down with some concrete saddles. screw anchors are good, but in wet sand might struggle.

If you bring it above surface our issue is bending / buckling or upheaval.

Only other option is build a causeway from stone and place the pipeline in that, above the highest water level. Seems rather drastic to me.

Or re-route it?

We have about 5% of the information someone will need to do a proper costed assessment of the options.

someone needs to recognise that sand is not a great material when it gets exposed and wet....

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

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

the cover and scour protection needs to be restored or you will lose the entire thing. access to the pipeline is the least of your worries.

the line is built near the water. it certainly must have been designed assuming a very high water table. now that the cover is eroded away, it is definitely subject to flotation as well as wave action, scour and lack of foundation support. you might try sand cover, geotextile and an articulated concrete block mattress (ACB) anchored over the top. Alternatively, some other type of revetment such as rock might work to both anchor and protect it. You will need to backfill all the low areas on the back side if you want surface vehicle access over the pipeline, otherwise plan on boat access.

coating and corrosion issues should have been addressed in the original design. if not, than complete replacement and relocation might be a good option.

http://www.km.kongsberg.com/ks/web/nokbg0397.nsf/A...

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

It appears that the pipe has some cover. Was flowable fill used during the original installation?

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

(OP)
Thank you all for your valuable input..
As conclusion 3 options can be consider:
1) Reroute the submerged part keeping in mind that the bottom of pipe having enough clearance from the Highest possible water table.
2) Drain the water and put gatch upto 1 meter hight above the water level + 200 mm fine sand, move the pipe up to the gatch level put 500mm berm above the pipe.
3) Keep the pipeline @ current level and try to restore the cover and protections bu means of :
*screw anchors
*Rock Dumping
*Sand cover and concrete block mattress
Relocate the monitoring and checking points to higher level (to be accessable), assessment of coating and CP System.

Feasibility and Cost estimation for each proposed option is under progress.

If any inputs or new ideas please advise....

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

1) move it above the highest recorded tide

2) check the significant wave height and runup at MHHW level and make sure it doesn't overtop the berm. check scour at MLLW level with the significant wave

RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

1.) Somebody already thought they were doing that.
2.) No fine sand. And rock armor it.
3.) Better still.


RE: Main Oil Pipeline have been submerged under water, looking for Rehabilitation suggestions!!

Are the conditions the same for the entire 16 km?

Based on the typical pattern of shoreline erosion and deposition that one would expect near the ocean shoreline, one would think that it is prudent to move the pipeline away from the beach.

That would be a start. You also have not mentioned anything about the possibility of typhoons or storms, rising sea level, possible terrorist target, etc.

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