NEWS
Offshore savings
Condition-monitoring sensor could cut maintenance costs for motors used on oil rigs
POWER AND AUTOMATION technology specialist
ABB has developed a sensor that could
greatly improve the maintenance routine for
small motors used in offshore oil production.
The device, called Wivib — short for wireless
vibration sensor — remotely collects data on the
vibrations of a motor to identify abnormalities in
its performance so that preventative maintenance
can be performed. It was recently
awarded the Spotlight on New Technology prize
at the Offshore Technology Conference in Houston,
one of the industry’s main trade fairs.
The Wivib system consists of an accelerometer,
temperature sensor and wireless
communication technology in a unit about 10cm
long which is mounted onto a motor near the
bearing. Encrypted data about the motor’s performance
is transmitted using the WirelessHART
standard to a central computer, where it can be
analysed to identify early signs of bearing failure.
Motors showing wear and tear can then be
swapped out for maintenance.
The system sprang from an R&D programme
sponsored by the Norwegian Research Council
under the Petromaks programme, which investigates
new technology for the oil and gas
industry, as part of a project focusing on condition
monitoring.
The original project identified great potential
in monitoring small motors, and the oil companies
involved, with SKF and Sintef, contacted
ABB in late 2005 to develop the device. Sintef
focused on the microelectronics, ABB on the
wireless part and instrumentation, and SKF contributed
knowledge about condition monitoring.
Oil companies including BP and StatoilHydro
also contributed to Wivib’s development.
Borghild Lunde, vice-president technology in
ABB’s oil, gas and petrochemical business unit,
said: ‘The pre-project developed the primitive
technology and ABB was approached to take it
to market in co-operation with the oil companies.
We developed the prototype through the
programme and now we have funding for the
pilot testing.’
Wivib will replace current procedures
whereby each motor is sent ashore for routine
maintenance every five years. This is costly and
time-consuming, especially if no repairs are
required.
Egil Birkemoe, sales and marketing manager
for ABB’s enhanced operation and production
division, said: ‘What oil companies wanted was
a system that would change the maintenance
regime for these motors. With Wivib, you can
detect degradation on the equipment and see it
online. Then you don’t have to send every one
8
ashore for repair every five years; you just take
out the ones that need it. This represents a shift
to condition-based maintenance.’
Wivib polls the motors regularly at intervals
set centrally. To save battery power, they are
usually checked about once a week, but this
could be set to be more often, or based on particular
events.
Birkemoe said the biggest challenges in
developing Wivib was making it suitable for the
offshore environment. It had to be ATEX certified,
a standard for apparatus destined for explosive
environments. It also had to be small, light and
low-cost, because many would be required in an
average rig.
The WirelessHART communications protocol
used by Wivib was ratified as recently as last
September, but is set to be the standard
adopted by all instrumentation vendors.
‘If you look at the cost of installing the wireless
infrastructure, it is fairly high,’ said
Birkemoe. ‘If you have one common standard
across manufacturers, that will take down the
cost because you can use the same infrastructure.
It also has low power consumption, which
The Wivib system will keep a regular check on small motors used in offshore oil production
means the battery should work for up to five
years before you have to change it.’
Although designed for the oil and gas industry,
Wivib could be used in a wide variety of
applications, Lunde believes. ‘It can be used in
all places where you have vibration, and as
the price level is quite low, it could be adopted
by other industries,’ she said. ‘Generally in oil
and gas, as long as it doesn’t weigh much and
has a small footprint, that industry is willing to
pay more.
‘But at this cost level, with low installation and
maintenance costs and reduced maintenance of
equipment, we believe shore-based industry will
also adopt it.’
Wivib has been tested with oil companies in
an onshore laboratory. The next stage is to agree
a plan to put Wivib into production and carry out
a full offshore pilot study. ABB plans to have a
commercial version available in 2009.
‘As ABB delivers a lot of automation, safety
and electrical systems, condition-based monitoring
and maintenance is becoming more and
more important for us,’ said Lunde.
Berenice Baker
the EnGIneeR 2–15 JUNE 2008
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