An intelligent pig
Ultrasonic inspections for small diameter pipelines

Every year, around 30,000 to 40,000 kilometers of new pipelines are added to the existing network of more than three million kilometers of oil and gas pipelines which already straddles the globe. Large sections are now starting to show their age – a fact which will be reflected in an increased need to inspect the pipelines in years to come. This means that non-destructive inspection techniques with intelligent pigs have an increasingly important role to play.

A“pig” is an inspection device which is used in long-distance pipelines to automatically collect data relating to wall thickness, corrosion, deformation and cracks—while the pipeline is in operation. NDT Systems & Services have specialized in measurements using ultrasound technology, as this makes it possible to not only inspect pipes for corrosion damage and measure the thickness of the walls, but it also offers early detection of cracks in the metal. Even recently, the lack of available technology made it impossible to use intelligent pigs in pipelines with a diameter of less than 8 inches.

This has now changed with the new LineExplorer, the first pig capable of performing ultrasound crack measurements in pipelines with smaller diameters of 6 and 8 inches (DN 150 and DN 200). As well as checking for cracks, the pig can also be used for corrosion and wall thickness measurements. It operates at an inspection speed of up to 2.4 m/s in corrosion/wall thickness mode and up to 1.5 m/s in crack detection mode. Thanks to its extreme flexibility, the pig can handle any pipeline routing configuration, including tightly curved pipeline sections with a bend radius of up to 1.5 D.
Modular construction
In its 8-inch configuration, the pig is equipped with 112 sensors (the 6-inch configuration has over 80) which are housed in a flexible sensor carrier. These sensors collect the measurement data which are then evaluated after the inspection using special software. Tailoring the NDT technology to a customer’s specific requirements is very straightforward, as all NDT pigs feature a modular construction—all that needs to be done is to configure the standard basic module with the necessary sensor carrier.
An innovative electronic system provides greater depth resolution and delivers more data about the penetration level of faults, allowing operators to make far more meaningful assessments of the condition of their pipelines. The improved efficiency of the electronic systems is also coupled with a reduction in size, as a result of which it was possible to shorten the length of the pig. The fact that the pig now measures just 2.7 m in 6-inch configuration means that it can also be used in applications where options for modifying the pigging station are limited. The
LineExplorer range is available in all standard pipeline sizes from 6 inches right up to a giant 56 inches (DN 1500). At sizes of 20 inches or above, pigs are also available in a combined configuration which allows wall thickness measurements and crack checks to be performed in a single pass.