Pressure pulses could help to clear subsea blockages

Low-amplitude pressure pulses could improve the clearance of blockages in subsea pipelines, after an Aberdeen-based company successfully tested the new technology.

The system, developed by Paradigm Solutions, can remotely locate and clear subsea blockages many miles away from a ‘topside’ platform above the water.

The user can precisely control the amplitude, length and frequency of the pulses using proprietary algorithms to optimise wave structure, as Hugh Mackenzie, technical director of Paradigm, explained to The Engineer.

‘We can fire pulses down a blocked line to determine exactly where a blockage is and once we’ve got the reflection back from this we can reconfigure the pulse to unblock the line.

‘Each pulse is putting a lot of energy into the blockage face, so it starts to break the bonds between the actual blockage and the pipe wall — and with the pressure behind that, we’re pushing the blockage out along the line.’

Paradigm Solutions will provide its technology as a service when pipeline owners or maintenance contractors encounter problems with flow — potentially saving considerable costs in lost product revenue, as well as salvage costs.

‘The unique aspect is that, depending on the set-up, we can tie in many kilometres away without having to get divers down to disconnect things — so essentially saving them an intervention with a DSV [diver support vessel], which costs an awful lot of money to hire,’ said Mackenzie.

During test phases, the Pipe-Pulse system successfully cleared a 4in (10cm) multi-phase flowline for Shell UK that had been blocked with sand and wax for 11 years. It also removed a stuck pipeline inspection gauge (pig) in a deep-water 8in flowline for Petrobras Americas in the Gulf of Mexico.

Paradigm Solutions revealed at the recent Offshore Technology Conference in Houston that it had secured a $250,000 (£154,000) contract to unblock a pipeline in the North Sea.