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underground pipelines inspection
- Thread starter engtalal
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A smart pig if the pipeline is designed for them. Some problems that could prohibit smart pigging are unbarred tees, reduced diameters, and bends with insufficient radius. Also, pigs require a means to launch and catch.
Look for a document “PIPELINE PIGS & PIGGING” on the internet by Pipeline Engineering & Supply Co. It is part of their Design and Application Manual. I have a pdf of the document I downloaded a few years ago; however, I took a quick look at their web site and did not see the document. You might drop them a note requesting this pdf. This gives a very basic discussion of pigging.
Look for a document “PIPELINE PIGS & PIGGING” on the internet by Pipeline Engineering & Supply Co. It is part of their Design and Application Manual. I have a pdf of the document I downloaded a few years ago; however, I took a quick look at their web site and did not see the document. You might drop them a note requesting this pdf. This gives a very basic discussion of pigging.
- Thread starter
- #5
Engtala,
Did you find the 33 page document, "PIPELINE PIGS & PIGGING" and determine that your pipeline cannot be pigged? Is this an insulated line that you are trying to check the insulation effectiveness? Please accurately define what specifically you mean by condition. I am not sure how you could check the condition of an above grade pipe line using a thermal technique let alone a buried one.
CRG
Did you find the 33 page document, "PIPELINE PIGS & PIGGING" and determine that your pipeline cannot be pigged? Is this an insulated line that you are trying to check the insulation effectiveness? Please accurately define what specifically you mean by condition. I am not sure how you could check the condition of an above grade pipe line using a thermal technique let alone a buried one.
CRG
DrillerNic
Petroleum
Echoing CRG's post; what are you trying ot check? Non-intelligent pigs can check things like ID and often have less restrictive bend radii limits. Intelligent pigs can get wall thickness, check for cracks etc. You might find that you can get temporary pig launchers for your line, provided it's piggable otherwise.
OrangeDog70
Mechanical
Inspection of pipeline without digging...let's see....
Check for leaks (Walk the line or shut-in pressure drop) is the most obvious and cheapest check, but tells you nothing about the intermediate condition and status of the line. Either it leaks or it don't.
Try a close interval survey (CIS) checking the potentials from pipe to soil and from pipe to same pipe at intervals. A gradient may indicate disbonding of the pipe coating and exposing the pipe to corrosion. This would be for external corrosion of the line. Corrpro can help with the DCVG survey. Look them up on the internet.
The above are the non-invasive checks. To go inside the line, borescope is you have access, but you are limited to what kind of access you have and only a local section of the pipe around the access.The line will have to be empty if it normally transports a dark fluid.
Smart pigging requires traps at the ends of the line. you will have to dig to put temporary traps in and then push the pig with compressed fluid from one end to the other. Geometry tools will gage the ovality of the line and let you know if there has been and gouging or deformation (from backhoe work) of the round pipe. Magnetic flux leakage will pick up internal (and external) wall loss of the pipe with some reasonable degree of accuracy. Cost is expensive and you will have to shut the system in for the test, but you will have definitive data on the condition of the pipe and which sections of pipe can be dug up and replaced.
Not knowing the length of the line and the size, I can't really give you a preferred recommendation to pursue. Hope these options help you get started on finding a solution to your problem.
Bob Lyons
PCS - Houston
Check for leaks (Walk the line or shut-in pressure drop) is the most obvious and cheapest check, but tells you nothing about the intermediate condition and status of the line. Either it leaks or it don't.
Try a close interval survey (CIS) checking the potentials from pipe to soil and from pipe to same pipe at intervals. A gradient may indicate disbonding of the pipe coating and exposing the pipe to corrosion. This would be for external corrosion of the line. Corrpro can help with the DCVG survey. Look them up on the internet.
The above are the non-invasive checks. To go inside the line, borescope is you have access, but you are limited to what kind of access you have and only a local section of the pipe around the access.The line will have to be empty if it normally transports a dark fluid.
Smart pigging requires traps at the ends of the line. you will have to dig to put temporary traps in and then push the pig with compressed fluid from one end to the other. Geometry tools will gage the ovality of the line and let you know if there has been and gouging or deformation (from backhoe work) of the round pipe. Magnetic flux leakage will pick up internal (and external) wall loss of the pipe with some reasonable degree of accuracy. Cost is expensive and you will have to shut the system in for the test, but you will have definitive data on the condition of the pipe and which sections of pipe can be dug up and replaced.
Not knowing the length of the line and the size, I can't really give you a preferred recommendation to pursue. Hope these options help you get started on finding a solution to your problem.
Bob Lyons
PCS - Houston
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