Cost is dependent on many factors, including pipe size and length & number of runs. Mobilization & set up time are considerable so the more runs and long runs on site the cheaper it is, say per meter. I'm more fa,miliar wiht pigging of cross country pipelines.
As far as benefits, assuming they are similar to cross country pipleines, there are many, including identifying dreformations that could resuklt in metal loss within the apex of the deformation, indications of multiple signature peaks within the deformation footprint, indications of metal loss within the apex, deformations ina girth or long seam weld that have depths greater than allowed by coed.
I would think you would want to run a base line so you will have something to compare against in future pigging runs to determine iof there have been any internal metal loss, deformations, strains outside the limits, etc..
There are differnt types of inteligent pigs, depending on what you want to accomplish and many qualified companies to do it. For example, high resolution MFL (magnaflux leakage) tool can provide sufficient information to detect deformations which contain metal loss, deformations located on the top of the pipe, deformations with multiple peaks, and deformations in welds
Geometry inspection tools can be used to assess the integrity of deformation anomalies to any industry acceptance limit. Hoewver, multi channel tools are required if a detailed analysis of deformations is to be performed. Multi channel geometry tools provide deformation depth and strain information. Just a catution if you go this route (or actually any route), you will want to field verify the initial resulots of the deformation strain values provided by the vendotr until they demonstrate a reliable ability to make accurate predictions.
There is one I've heard aobut and gotten some basic literature on, but have never worked around it, and that is called Ultrasonic Fleximat (built in the UK, but should have US distributors). This tool as I understand it, allows for continuous, non-invasive monitoring of pit growth on pipelines and vessels. It's composed of a flexible multi-element array of ultrasonic transducers that can be permanently bonded to the surface, has an operating temperature range from -40C to 75C, and data retrieval can either be manual or automated. One of the uses is for the monitoring of pit growth after it has been discovered by an MFL Tool.
Again, once you decide what you ewant to accomplish, there are an array of choices. I've only touched on a few.
Greg Lamberson, BS, MBA
Consultant - Upstream Energy
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