Going with the flow

​​​​Experts in medicine, physics, engineering and industry are combining to tackle a costly problem in oil and gas – “thrombosis” in subsea pipelines caused by hydrates.

Their aim is to better quantify the effect of hydrates in pipelines to improve operations, avoid upsets and enhance production.  World-leading research is underway in Perth involving engineers from Woodside and scientists from the University of Western Australia (UWA) at the Harry Perkins Institute for Medical Research.

One of the Woodsiders, principal flow assurance engineer Paul Pickering, explains how the “thrombosis” occurs.  “When oil and gas flow through subsea pipelines, water is usually present,” Paul says.  “At the local temperatures and pressures, ice-like solids called hydrates can form, possibly accumulating and producing a ‘thrombosis’ causing production losses.”

Paul and technology development manager Nino Fogliani were among a group who applied in 2014 for funding from the Australian Research Council to investigate the flows of hydrate, oil and water slurries in pipelines.   The group included professors Eric May, Mike Johns and Zach Aman from UWA’s Fluid Science and Resources Division.  Their application was successful and this year they began investigating the complex phenomenon of hydrate slurry flows.

Mike Johns, a world-leading authority on nuclear magnetic resonance and magnetic resonance imaging (MRI), acquired his skills at the Magnetic Resonance Research Centre at Cambridge University.  It was Mike’s idea to use a state-of-the-art MRI machine to non-invasively image hydrate slurry flow fields formed using high pressure methane.

The machine in question resides at the National Imaging Facility (NIF) at the Perkins Institute.  Unsurprisingly, the NIF was less than enthusiastic with the idea of introducing a high-pressure flammable gas such as methane into its multi-million-dollar machine.  So Mike modified the experiment.  Instead, he proposed cyclopentane – a liquid that forms hydrates at low pressures and low temperatures.  This means the system does not have to be pressurised as it would with methane.  The NIF agreed to this modification, and the hydrate slurry imaging project was born.

A hydrate slurry flow loop was built at UWA and it was transferred in November to the NIF and installed in the MRI facility to perform the preliminary flow loop commissioning tests.  These initial tests were successful.  “We’ve now taken the first step on a journey to an accurate understanding of hydrate slurry flows in subsea pipelines,” says Paul.  “Using advanced methods applied in medical science, we’re confident we’ll be able to reveal the full beauty of slurry rheology through the power of very strong magnets!”

Hopefully, it will also help devise a solution to subsea pipeline thrombosis, improve design and operations and enhance production.

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Trunkline Q4​ 2016