North Ridge Pumps Ltd

Heavy Duty Submersible Seawater Lift Pump

Product

A company involved in Oil and Gas Engineering recently contacted us who had a very particular requirement. They wanted a fully submersible seawater lift pump able to handle some of the toughest conditions on the planet in the North Sea.

The pump they required would be helping to flush sand filters onboard their offshore oil rig, and would be tasked with keeping production rolling, and the platform clean and safe.

Why are sand filters important on an offshore oil rig?

Sand filter systems are absolutely vital to the smooth running of any offshore oil or gas platform. Sand is produced by the drilling process, and this can quickly work its way into various systems, disruptingproduction, damaging equipment and surface facilities, and severely impacting profitability. Sand filters help to ensure that the sand by-product is kept out of critical systems.

Pumps for Seawater Lift

There are 3 methods commonly used to transfer seawater to offshore platforms:

• Semi-submersible vertical line shaft pumps or immersed pumps which have the motor located above the pump assembly. These can be installed in the platform legs and use a motor located outside the fluid and pump column immersed in the fluid to extract the seawater.
• Self Priming Pumps providing the vertical suction is less than 8M.
• Fully submersible pumps with the motor positioned below the pump in the sea in which there are 2 variants. Borehole pumps which are a type of multistage submersible pump designed to deliver high flows at high pressures or submersible pumps which contain a single impeller designed to deliver high flows are relatively low pressures.

What was our specification for this demanding application?

At North Ridge Pumps, we can specify a wide range of pumps for a variety of industrial applications.

Moreover, we’re not limited to just one pump technology. Our unrivalled expertise enables us to offer a tailor-made solution, not something off the shelf. So we always choose the most cost-effective pump for any specific client, project and application.

Very specific requirements

For seawater lifting applications like this, the pump specification usually requires materials able to deal with prolonged contact with seawater such as nickel aluminium bronze, if high pump pressures are also required.

Alternatively, if seawater temperatures are particularly warm, duplex stainless steel will be chosen.For this client, who required a seawater lift pump able to withstand rough conditions on a North Sea oil rig, we designed and developed an 8” fully submersible borehole pump made from duplex stainless steel. With 45m of cable, the pump will deliver 100m³h at 100m head.
The Motor and pump are shipped separately, and connected on site to enable easier handling on site and also to ensure the pump does not become misaligned during transit, lifting or loading. When the motor is fitted it will be over 2.5M long.


If you have any application needing the transfer of fluids, solids or viscous liquids, and aren’t sure which pump to specify, speak to North Ridge Pumps to see how we can help.