Oil and Gas subsea operators across the world are adopting a GE Industrial Internet technology developed in Norway. The GE Measurement and Control Subsea Condition Monitoring system (also known as the ‘Cage’) measures sound and electrical signals emitted from subsea equipment, often an early warning sign of developing leaks and other issues. The listening ‘ear’, an array of sensors in a 500-pound ‘birdcage’ dome that sits on the sea floor or on subsea equipment, was developed at the GE Measurement and Control site in Bergen, Norway. A 210 metre (MSL)* deep water facility at the Bergen site also provides deep water testing for the technology.

1. Oil & Gas
industrial internet in action
SOUNDS FROM THE DEEP –
A Norwegian technology success
keeping an ear to the ocean
Oil and Gas subsea operators
across the world are adopting a
GE Industrial Internet technology
developed in Norway. The GE
Measurement and Control Subsea
Condition Monitoring system (also
known as the ‘Cage’) measures
sound and electrical signals emitted
from subsea equipment, often an
early warning sign of developing
leaks and other issues.
The listening ‘ear’, an array of
sensors in a 500-pound ‘birdcage’
dome that sits on the sea floor or on
subsea equipment, was developed
at the GE Measurement and Control
site in Bergen, Norway. A 210
metre (MSL)* deep water facility at
the Bergen site also provides deep
water testing for the technology.
Engineers designed the eardrum
of the system from special crystals
that respond to sound wave
vibrations and convert them into
electricity (Engineers call this effect
‘piezoelectricity’). A single device can
listen to sounds within a 1,600 foot
radius.
In addition an array of attached
carbon rods can detect changes
in the magnetic field generated by
electrical cables, pumps, motors
and other electrical equipment
in a subsea environment, and
spot ground faults or defective
isolation. The device sends this
sound information to a seaborne
control room where the data is
analysed to help plan maintenance
and component replacement
programmes.
“An acoustic signature from a piece
of equipment is like a fingerprint
from a human. No two leaks
or pumps are going to sound
the same. We can filter out the
background noise, like marine life,
and listen only to things we want”,
explains Fabian Dawson, sales
manager from GE Measurement
and Control. “You can determine
the revolutions per minute of a
compressor from the acoustic signal
and then you can determine how
hard it is working from the electrical
signal. Taken together, they will tell
you what the efficiency is.”
Another benefit is that the sensors
are located at a distance and are
detached from the monitored
equipment so do not interfere with
on-going operations or processes.
8 continues over
above: Acoustic leak detecting
technology - known as “the Cage”
below: “Birdcage” on platform
*Mean sea level
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2. The GE team is now developing a
huge data library of sounds from
existing subsea installations to
add to the predictive capabilities of
the system. Dawson comments,
“You are looking at the correlations
between the pieces of the
equipment emitting both the
electrical and acoustic signals, and
sometimes there is a signature
there you can’t trace. We call them
rogue sounds.” GE data scientists
and engineers then work to develop
algorithms to spot similar odd
sounds in the future.
The system can be 10,000 times
more accurate than traditional
mass balance systems that
measure differences in the amount
of oil and gas flowing through the
pipes to detect leaks.
The Condition Monitoring system is
already working at some 130 sites
in the North Sea operated by Statoil,
ENI, and Shell, and off the coast of
Africa. GE has also introduced it to
American customers at the 2013
Offshore Technology Conference in
Houston, Texas.
Shell case study
“Water is a very good medium for
propagation of sound waves. That
is one of the reasons why whales
communicate so well,” says Oddvar
Christiansen, Software Development
Manager at GE Measurement and
Control in Bergen.
Engineer Christiansen and
his team are responsible for
developing the software that
supports the ‘birdcage’ GE Subsea
Conditioning Monitoring system.
“…..gives a great ‘comfort
feeling’ to operations, when
you hear what you are
doing in the control room is
actually happening”
Jane B. Kendall, Shell
A recent test project for Christiansen
and the team has been in the
Ormen Lange natural gas field off
the Norwegian coast. Here the
GE Condition Monitoring system
was located at the base of a large
test pit operated by Shell where
a number of subsea equipment
items including a 12.5 MW subsea
compression train, a condensate
pump, a 132kV transformer, a
circuit-breaker and advanced
VSDs (Variable Speed Drive) and
separator were all being qualified
for deep water deployment. The
‘birdcage’ system was monitoring all
components residing in the pit and
the interactions between them.
During its installation the
Conditioning Monitoring system has
provided the customer team with
significant operational benefits.
A system power trip resulted
in active magnetic bearings
momentarily losing control of the
compressor shaft and contact with
the landing bearings. These events
were detected and reported by
the system in real time. An audio
recording of the event also helped
troubleshooting work.
When no flow was observed
gemindsandmachines.eu
on the flow-meters during the
condensate pump start-up and the
commissioning log reported the
machine had been running at 600
RPM (revolutions per minutes) before
it tripped, further investigations were
needed. Possible explanations were
close valves, dysfunctional flowmeters or faulty variable speed drive
configuration. By combining the
acoustic signature from the pump
with the electric field signature from
the VSD it was revealed the flow
meters were correct and pump
rotation had not occurred due to
wrong settings in the VSD.
Other events during the project
included detection of an unexpected
transformer shut-down, observation
of unstable compressor conditions
and positive tracking of machine
speed and load.
“Audio of system trips helped
us to identify a non return
valve opening and closure
that we did not expect”
Jane B. Kendall, Shell
Jens Abrahamsen, Business
Manager for this technology at GE
adds, “The presence of the Condition
Monitoring Device provided the
customer with strong gains. The real
time acoustic feedback provided
operational reassurance and the
data from the system provided
another viewpoint when equipment
incidents took place. The quantity of
data also provides potential to look
at equipment performance trends.”
Joanna Osborn
Lead Communicator Global Services
GE Oil & Gas
T +39 055 423 3615
M +39 345 377 6304
E Joanna.Osborn@ge.com
© 2013 General Electric Company – All Rights Reserved