Pipeline inline inspection devices, also known as “pigs”, can provide critical early warning of potential failure points in an oil and gas pipeline before a problem occurs. But how do you know if the pig is accurate?
When working correctly, inspection pigs can detect minute flaws in pipelines before they can be detected by visual inspection. Pigs can also efficiently inspect miles of pipeline at a time, flowing through the pipes along with the gas or liquid. Inspection pigs are designed to detect cracks, pits, thinning pipe walls or coatings, and signs of corrosion so they can be fixed proactively. However, there are very few facilities that are able to measure the accuracy of the devices.
Battelle operates one of only a small number of pipeline inline testing facilities in the world. At its Pipeline Inline Inspection Facility in West Jefferson, OH, researchers evaluate pigs to find out how accurately they pinpoint pits, cracks, thinning walls and other pipeline flaws. The facility has one of the largest archives of pipes in the world, with pipe diameters ranging from 16” to 42” and various materials characteristics. The pipes all have known cracks and flaws that have been carefully measured. By pulling the inspection pigs through the pipes using a cable, researchers can see which flaws are picked up and which are missed.
The process acts as an important quality control check for manufacturers and oil and gas pipeline operators, as well as for the Department of Energy (DOE). Manufacturers contract with Battelle to evaluate or calibrate new pigging devices before they go to market. Pipeline companies may ask researchers to test and compare several different kinds of inspection pigs to determine which one is best suited to their pipeline characteristics. Using the carefully calibrated quality tests, Battelle scientists are able to help manufacturers improve the accuracy of the pigs and buyers make informed decisions on pig selection.