Bats Inspire Detectors to Help Prevent Oil and Gas Pipe Leaks
Engineers
have developed a new scanning technique inspired by the natural world that can
detect corroding metals in oil and gas pipelines.
With
thousands of kilometers of pipelines used to transport oil and gas over huge
distances globally, leaks are a major issue costing millions annually and have
the potential to cause accidents and injuries as well as significant
environmental damage.
Typically,
corrosion in oil pipelines is measured with ultrasonic or electromagnetic
techniques. However, these are not practical for underground pipelines, or for
pipelines covered with insulating layers of concrete or plastic.
The
new system, developed by Engineers from Lancaster University, the National
Physical Laboratory, and a technology company, Hybrid Instruments Ltd, exploits
the 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 not always are 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 Ltd.
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 in a laboratory on samples
of carbon-steel of different thicknesses.
The
researchers 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.
"The
combined beams of neutrons and gamma rays in parallel bouncing back to an array
of detectors yield a comprehensive and fast representation of the inner
structure of steel," said Mauro Licata, Ph.D. researcher on the project
from Lancaster University.
"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."
"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," said Professor Malcolm Joyce of
Lancaster University and Hybrid Instruments Ltd.
"This
is a great example of NPL's world-leading neutron facilities being used for
innovative science with a positive impact," said Neil Roberts of the
National Physical Laboratory.
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/γ ray backscatter: a biometric approach," which has been published by the journal Scientific Reports.