How to repair submerged pipeline

What kind of pressure is the line under.

If understood correctly the 6" crude oil pipe spans the river of about 110 m hanging about 0.7 m below the surface of the water. the break occurred in the river about 10 m from one side.

What is the material and class of pipe?

Did the break occur from something floating down the river?

What is the break like?

What is the velocity of flow in the river?

A permanent solution of replacing and lifting the pipe out of the water and support it with some sort of structure or cables.

Another fix might be to place concrete around the pipe. but it will cause impeding.

A temporary fix for rigid steel pipe could be :

If cracked : a double sided saddle can be manufactured and placed over leak and bolted together (with appropriate sealing material)

If broken: A sleeve type of coupling with bolt on type of o ring seals at both ends.

(sort of expansion joint - you have to shop around)

Quick fixes should be scheduled for replacement as soon as reasonably possible.

Oil pollution must be avoided.

There are metal clamp repair sleeves with a rubber patch built into them. Just wrap it around the pipe and tighten the bolts.

Sir,

At the depth indicated ( and to determine very clearly that the break does not come from a pipe that has been irreparably affected by either rust or electrolysis, my first suggestion would be to build a small cofferdam. This could use light steel piling, marine ply-wood so that the area could be kept dry for welding. This cofferdam could be of such size as to allow a welder to remain inside ( in the dry) to conduct the repair and ensuing welding operation. The depth is such that in my opinion a well prepared coffer-dam will give you the best and safest result (even if you have to place a layer of rapid setting marine type cement at the bottom therof . Of course this could include in one corner: a sump, or low point, from which any seepage can be pumped out continuously during the repair . Another and cheaper method for you is to use, small hessian bags filled with sand and simply build the coffer dam with a required number to help you stem the water ( You will still have to treat the bottom of the coffer-dam as indicated above for control of :undergound seapage)

Of course welding under water is always possible. However you need to have very good workmen who generally have been tested to API standards (American Petroleum Institutes , who regulates world wide the oil industry ) . I strongly suggest that unless you are certain of what you are doing do not play around for the fear of contamination of water course,rivers etc.

Labor

I've no personal experiance, but I believe you can use an internal sleeve repair, I've checked the internet and there's plenty of info under internal pipe sleeve repairs. Though looking at the post you may not have access to the internals of the pipe necessary for repairs? Just a suggestion?

How deep is the river at that spot?

The location would make me create a dam round the damaged spot. In shallow water you can use sand and stones, in deeper water you can use the metal profiles they use in construction. (they go up to 10m of water and even more if you want.

Remove the water inside the zone below the pipe..

Cut the bad piece out and weld a new piece in between.

What is the reason for the leak: an accident or age? The second would make me install a new river crossing and remove this leaking crossing.

I would support Hendrik's view with respect to clamps. Clamps of appropriate diameters with sealing materials or ring kind of o-rings could be used.

Wet welding could also be done but the risk of explosion of the pipeline. But if appropriate safety measures are put in place i.e purging the pipeline, stop production,etc then wet welding can be considered.

I know that cold work is more preferable to problems like this.

Please act fast so that oil pollution can be minimised.

'Crossing a waterway...'... Is this within a refinery/facility, or does it fall under DOT jurisdiction? Assuming the latter, then clearly the OQ ruling comes into play here (49CFR, amendments regarding pipelines carrying gas, oil, hazardous materials). CFR also stipulates certain corrective actions, allowable and unacceptable practices. We install Plidco repair clamps routinely on lines in the Gulf of Mexico (at "all" water depths, all diameters). Is the line weight-coated? Did inadequate cathodic protection contribute to the leak? More data is needed for a full assessment, but, certainly "something" needs to be done quickly! ("PS"; if pressure is low enough, the syntho-glass system has DOT recognition, and can be Very effective on smaller diameters... underwater-curable; http://www.neptuneresearch.com/Pipe_Reinforcement.cfm )

We use a company called Colt Atlantic Services, Inc. to repair many pipelines, flange connections etc. while under pressure. They have successfully repaired leaks in many 850 lb. steam lines at our mill. They use a saddle clamp sleeve type mechanism to encase the area of the leak and then inject a high pressure hydraulic sealing compound into the void via connection on the sleeve. The good thing is that they are very adaptable for many different types of leaks and they make all of their sleeves in house custom to what is needed for each job. They are very good at stopping leaks when things can't be shut down and this is a large part of their business.

pipewelder