Wivib’s offshore savings

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 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 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