New neutron-based method helps keep underwater pipelines open
Neutrons detect clogs non-destructively through the metal walls of
pipelines

Date:
January 21, 2022
Source:
Technical University of Munich (TUM)
Summary:
Industry and private consumers alike depend on oil and gas pipelines
that stretch thousands of kilometers underwater. It is not uncommon
for these pipelines to become clogged with deposits. Until now,
there have been few means of identifying the formation of plugs
in-situ and non- destructively. Measurements now show that neutrons
may provide the solution of choice.



FULL STORY ========================================================================== Industry and private consumers alike depend on oil and gas pipelines that stretch thousands of kilometers underwater. It is not uncommon for these pipelines to become clogged with deposits. Until now, there have been few
means of identifying the formation of plugs in-situ and non-destructively.

Measurements at the Research Neutron Source Heinz Maier-Leibnitz (FRM II)
at the Technical University of Munich (TUM) now show that neutrons may
provide the solution of choice.


==========================================================================
Oil and gas pipelines are the arteries of our energy supply. As with
the Nord Stream pipelines, they transport the sources of energy over
long distances underwater to storage and production facilities on land.

But it's not just supply bottlenecks, as we have them now, that can lead
to shortages. Under certain conditions, the mixture in the pipelines --
which typically comprises gas, oil, and water -- can become very viscous
and even form solid phases.

Especially inconvenient for operators are solid hydrates that form
from gas and water, for example when the mixture cools down to the low temperatures of the seabed during longer pipeline shutdowns.

Previous approaches do not work underwater For a clog to be
remediated in-situ, the affected section of the pipeline must first be
found. Localizing clogs from the outside is challenging, since they can
form anywhere along the length of the pipeline.



==========================================================================
To date, thermal imaging cameras and gamma rays are used to detect
the clogs.

However, neither of these methods works underwater. Ultrasound, on the
other hand, has no problem penetrating water, but the hydrate blocks
can only be detected at close range from outside the pipeline wall.

This constraint poses practical difficulties because underwater pipelines
are laid at depths of up to 2000 meters and are often naturally covered by seabed materials like sand or silt. Another technical challenge associated
with acoustic methods arises from the lack of a clear difference between
the acoustic impedances of the hydrate phase and other phases of the
crude oil mixture, which makes discrimination difficult.

Neutrons -- the perfect probe TechnipFMC, a company with around
20,000 employees worldwide that specializes in subsea pipelines, was
"Looking for a more efficient method to find the plugs in a non-contact, non-destructive and reliable way despite thick walls," says Dr. Xavier Sebastian, a project manager at the company.

As suggested by Dr. Sophie Bouat, CEO of Science-S.A.V.E.D. (Scientific Analysis Vitalises Enterprise Development), "Neutrons are the perfect
probe for the task at hand." She established the contact to the scientists
at the Heinz Maier-Leibnitz Zentrum in Garching near Munich.



========================================================================== "Using prompt gamma neutron activation analysis, light atoms and hydrogen
in particular can be detected very precisely," she continues. Since
the hydrogen content of hydrates and normal oil or gas is considerably different, it should be possible to detect blockages by measuring the
hydrogen concentration.

Feasibility study at FRM II Dr. Ralph Gilles industry coordinator at the Research Neutron Source FRM II carried out a feasibility study on this
topic together with other colleagues from the Technical University of
Munich and the Forschungszentrum Ju"lich.

Using the PGAA (Prompt Gamma Activation Analysis) instrument, which
utilizes cold neutrons from FRM II, the researchers established that
this approach can be used to differentiate between oil and gas and
the blockage.

At the NECTAR radiography and tomography facility and the FaNGAS (fast
neutron- induced gamma ray spectroscopy) instrument they used fast
neutrons from FRM II to show that a sufficiently large number of neutrons penetrate the metal walls of the pipelines to facilitate the respective measurement, and that the measurement also works well underwater.

A small neutron source detects plugs The results clearly demonstrate
that neutrons are ideally suited for this application. Moreover,
"Our experiments have shown that we can even distinguish an incipient
blockage from a fully developed one," says Dr. Ralph Gilles.

"That's very beneficial, because then one can even preventatively heat a
pipe segment to melt the blockage before it fully develops." In practice,
a mobile detector with a small neutron source will move back and forth
along the pipeline to look for plugs. "We are very pleased that, with
the help of the measurements at the research neutron source, we have
now found an efficient method that makes it much easier to detect these
plugs in the future," says Dr. Xavier Sebastian.

Besides scientists of the Technical University of Munich, researchers
of Forschungszentrum Ju"lich and RWTH Aachen University contributed to
the analysis. The contact to the company TechnipFMC was mediated through
the company Science-S.A.V.E.D. (Scientific Analysis Vitalises Enterprise Development). Access for beam time was paid by TechnipFMC.

========================================================================== Story Source: Materials provided by
Technical_University_of_Munich_(TUM). Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Sophie Bouat, Ludovic Pinier, Xavier Sebastian, Adrian Losko, Rudolf
Schu"tz, Michael Schulz, Zsolt Revay, Zeljko Ilic, Eric Mauerhofer,
Thomas Bru"ckel, Ralph Gilles. Detection of hydrate plugs inside
submarine pipelines using neutrons. Nondestructive Testing and
Evaluation, 2021; 1 DOI: 10.1080/10589759.2021.1990284 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220121124848.htm

--- up 6 weeks, 6 days, 7 hours, 13 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)