The technology facilitates the inspection of heavy wall liquid and gas pipelines and has been applied in European and South American offshore pipeline inspections with excellent results.
Customers are queueing up to use Halfwave’s acoustic resonance technology (ART) for the inline inspection (ILI) of pipeline systems. The technology – which is marketed under the name ART Scan – can be used to inspect 14 to 48 inch (356 to 1,220 mm) diameter heavy wall liquid and gas pipelines.
Popular for projects
Halfwave was awarded three major tool provision projects last year and two more recently from an operator in the Gulf of Mexico, which will involve the design, engineering and manufacture of several high accuracy ART Scan tools, each one tailored to the individual client’s specific needs.
Key features of the units are their ability to:
undertake inspection runs of up to 1,200 km
cope with varying flow rates in the same sections »» traverse pipe diameters of 16, 24 and 28 inches (407, 610 and 712 mm) in the same run
pass through multiple subsea wyes, including lateral entry at low flow rates.
ART Scan can detect internal and external metal loss down to 0.5 mm, with an accuracy of ±0.2 mm at inspection speeds of up to 5 m/s. In addition, repeat runs over the same section of pipe have proven the technology’s reliability.
The performance of the tools has attracted offshore and onshore pipeline operators, especially the latter, who are eager to reduce the number of verification digs necessary over extended pipeline routes.
ART Scan in action
In a recently completed inspection of a 20 inch (508 mm) oil export pipeline in the Valhall field in the Norwegian North Sea, operator Aker BP said one of ART Scan’s biggest advantages was the technology’s ability to work through substantial wax deposits. This eliminated the need for pig cleaning runs and reduced the overall inspection time from what could easily have been twenty days to just six.
Similar positive feedback has also been received from another client operating in the Gulf of Mexico.
State-of-the-art for ILI
Halfwave has developed a new form of ultrasonic testing (UT) for pipelines based on ART. The technique uses a series of broad acoustical sensors to perform an integrity inspection of pipelines for metal loss and damage, which correlate particularly well with the thickness of even the heaviest pipe wall.
ART is unlike conventional UT in several respects. A key difference is that there is no requirement for a liquid coupling medium to transmit the ultrasound signal into the pipe wall, so Halfwave’s tool is able to inspect live gas pipelines. ART’s signals also penetrate coatings, loose debris and surface deposits – notably wax – more effectively than conventional UT signals, thereby reducing pre-inspection cleaning requirements.
Another notable feature of the technology is the signal emitters and receivers may stand off the pipe wall by several inches; however, the actual spacing does not affect wall thickness measurements.
Hence, ART pipeline pigs are uncommonly flexible and can negotiate lines with the sort of constrictions and diameter changes that would scupper conventional UT tools.
This was borne out during trials with a leading operator in the Gulf of Mexico, with a representative saying their greatest value driver was the ability of the pig to travel from A to B without getting stuck in the pipe.
This article was featured in the Fall edition of Pipelines International. To view the magazine on your PC, Mac, tablet, or mobile device, click here.
For more information visit the Halfwave website.
If you have news you would like featured in Pipelines International contact Assistant Editor Chloe Jenkins at email@example.com