Magnet motor key to subsea step change

Full qualification testing of a 3.2MW multiphase subsea pump system capable of operation in pressures up to 5000psi has now been completed, FMC Technologies and Sulzer Pumps confirmed during Stavanger’s ONS show.

Unveiling the new system, Tore Halvorsen, FMC’s senior VP of subsea technologies, described it as a key component in the company’s goal of developing a full subsea ‘factory’ by the end of the decade.

‘We have a technology roadmap that takes us from today’s position all the way to the ambition where we think we can have a truly subsea based system, and each year we have targeted what we intend to develop and have qualified,’ Halvorsen said.

The new 5000psi-rated, 3.2MW multiphase subsea pump system during final qualification testing.

FMC director of subsea processing Rob Perry said combining Sulzer Pumps’ proven hydraulics with FMC’s high-speed permanent magnet motor technology created what will be a robust and efficient pumping system.

The pumping system’s permanently magnetized motor.

‘The motor is new technology, the hydraulics are field proven, and the systems around the pump really call on FMC’s subsea experience,’ Perry said. ‘If you’re an operator, you like to have multiple choices. And this product, where it starts to differentiate is that it gives you a broader application envelope than what’s currently on the market.’

Multiphase pumps enable the entire production stream to be gathered and boosted. The new pump, Perry said, differs from pumps powered by induced electrical currents in that the permanently magnetized motor reduces the overall package size while allowing a wider liquid gap between the pump’s rotor and stationary elements. The resultant reduction in drag losses means the pump can operate faster or, at an equivalent rate of an induction machine, with less energy use.

According to Perry, a 6MW multiphase pump FMC is developing will be able to withstand pressures of up to 15,000psi and be designed primarily for the Paleogene prospects in the deepwater Gulf of Mexico. ‘If you go with a conventional motor, there’s a limit to how far you can go,’ Perry noted. ‘With this technology, you can break through that limit. The motor is the key.’ RM