Woodside, UWA assess impact of pipeline marine growth

April 1, 2021
Woodside Energy is collaborating with OceanWorks at the University of Western Australia on offshore R&D.

Offshore staff

PERTH, AustraliaWoodside Energy is collaborating with OceanWorks at the University of Western Australia (UWA) on offshore R&D.

According to the latest edition of the company’s house magazine Trunkline, one of the programs concerns the impact of marine growth in offshore engineering.

Results suggest marine growth may help stabilize subsea pipelines. The teams were able to demonstrate that marine growth has the potential to disrupt vortex-induced vibrations (VIV) for pipelines, and that this could render span analysis/rectification procedures unnecessary.

VIV, which can occur when a current goes past or around a pipeline, is caused by unsteady flow behind the pipe. Marine organisms living on pipelines or cables such as barnacles, algae, and mussels, may alter the pipelines’ hydrodynamic profile, acting as a stabilizer.

UWA’s Terry Griffiths said: “We found that the fluffier the marine growth, the more it contributed to stabilizing the pipe or cable and drastically reduced the intensity of vortex-shedding, which is the phenomena that causes vortex-induced vibrations that can rapidly cause pipe fatigue failure.”

FutureLab is a collaboration between UWA’s Professor Ian Milne and senior metocean engineer Matthew Zed on improving the predictability of vessel responses to unpredictable ocean conditions.

They are also part of a team supporting development of a tool said to have improved the safety, integrity and operability of Woodside’s drilling campaigns.

The Vessel Operability Planning Software (VOPS) can determine the motion of a vessel directly from a full description of the ocean wave environment. Woodside has used the software to support drilling campaign scheduling, rig selection, mooring optimization and aviation.

According to Zed: “VOPS delivers big improvements on the engineering methods previously employed. The result is safer and more reliable operational planning and it has been instrumental in realizing significant savings to both schedule and rig configuration costs across our campaigns.

“It allows us to prepare for inclement weather and has now become a standard operational guidance tool for use in drilling campaigns globally.”

Development of VOPS included one of the first full-scale validations against high-quality measurements from a drillship in the open ocean, Woodside said.