Pipeline corrosion and leak detector inspired by bats
04 February 2020
Engineers have developed a new scanning technique that can detect corroding metals in oil and gas pipelines by using a method that mimics bats. Similar to how a bat uses differing wavelengths of ultrasound to detect its surroundings, the new system combines two separate types of radiation, fast neutrons and gamma rays, to detect corrosion.
Corrosion in oil pipelines, a leading cause of leaks, is usually measured with ultrasonic or electromagnetic techniques. However, those methods are not suitable for underground pipelines or for pipelines covered with insulating layers of concrete or plastic.
The new corrosion detection system has been developed by engineers from Lancaster University, the National Physical Laboratory, and a technology company, Hybrid Instruments. The system exploits reflected signals, known as ‘backscatter’, of a combination of isolated fast-neutron and gamma radiation.
Neutrons and gamma rays have useful complementary characteristics. Neutrons interact mainly with low-density materials like plastics. In addition, fast neutrons have a high penetrating power, so they are suitable for probing thick materials. Gamma rays interact mainly with metals and are not always able to penetrate very thick materials of high density.
The two radiation types produce a different electronic signal. This means researchers can retain data on both types of radiation simultaneously using a novel detecting device called a ‘Mixed Field Analyser’, previously developed by Lancaster University and Hybrid Instruments.
The system produces a pencil-like beam of probing radiation, of neutrons and gamma, which is directed at the steel section being inspected. The team tested the two imaging techniques in real time on samples of carbon-steel of different thicknesses and were able to see differences in steel thickness. The sensors also worked when an insulating layer was replicated, with concrete or plastic, indicating the likelihood that defects in steels, as well as corrosion and rust, would produce variations in the backscatter.
These results indicate that if used on real pipelines then potential issues could be more easily detected and resolved before oil and gas is able to escape.
“This system works a bit like the chirps made by bats. These chirps are a superposition of different ultrasound wavelengths, which bounce back to the bats’ ears. As well as highlighting the benefits of combining multiple reflection sensing techniques to detect for problems such as corrosion, our work further illustrates the significant potential that can be had from taking inspiration from, and mimicking, systems that have evolved in the natural world,” said Professor Malcolm Joyce of Lancaster University and Hybrid Instruments.
“Isolating neutrons and gamma rays backscattered from a steel surface in real time, in a way analogous to the way bats’ brains isolate backscatter ultrasound and thus avoid confusion with their own chirps, could help us isolate flaws in pipe walls more quickly and effectively,” Professor Joyce added.
The intention is that the detector system would be further developed and used to detect faults by pointing it at sections of pipeline from the outside. However, the investigators say more research is needed in the field of neutron detectors to make the system faster. The researchers suggest the technology could also be used in other applications, such as inspecting the integrity of structures such as bridges.
The research has been outlined in the paper ‘Depicting corrosion-born defects in pipelines with combined neutron/gamma ray backscatter: a biometric approach’, which has been published by the journal Scientific Reports.
Contact Details and Archive...