New kid on the block
Testing started this summer on a new subsea pump being developed by Baker Hughes, a GE company (BHGE). It’s no ordinary pump. It has no barrier fluid, for a start, reducing the complexity of umbilicals and reducing topside support requirements. The impellers rotate around a static central shaft, avoiding rotor dynamic issues associated with conventional pumps.
It could be the next step in subsea multiphase boosting, a space in which new technology is needed, according to Pierre-Jean Bibet, rotating machinery department, expert in pumping systems, Total E&P. Speaking at the Underwater Technology Conference (UTC) in Bergen this June, he said the uses for multiphase pumps have been expanding, including transportation of fluids to a floating production system, to increase production from reserves by lowering wellhead pressure and producing viscous fluids.
The future potential is significant, but for new projects to come on, the biggest challenge is the Delta P (differential pressure), he says. “The issue is the higher power requirement to generate more head (pressure), which means higher speed and more head per stage. With existing designs, you can generate Delta P of 210bar at 60% gas volume fraction (GVF), which is almost the starting point for long tiebacks and deepwater projects. We need cost effective multiphase systems for ultra deepwater and long tiebacks.”
