Software aids predictions of fracturing in offshore pipes

It is hoped the simulations could help oil and gas companies identify stronger or more flexible pipe materials that could help minimise the impact of a future large-scale accident.

The project began when researchers at the Massachusetts Institute of Technology’s (MIT’s) Impact and Crashworthiness Laboratory started to investigate whether their simulations of material deformation — honed over many years for automotive components — might also be useful in other industries.

The team uses a technique it calls fracture predictive technology that combines physical experiments with computer simulations to predict the strength and behaviour of materials under impact.

One approach it used is to spray samples of a material with a fine pattern of speckles, covering the surface with tiny dots, then subject them to different types of loading in a clamp.

A motion-capture camera, set up in front of the sample, takes images as it crumples, sending data to a computer, which plots the image’s dots along a grid to show exactly when and where deformations occur.

Through a variety of test conditions the team says it can determine a material’s overall mechanical properties, such as its strength and ductility, and ultimately create a simulation to predict a material’s behaviour in any configuration, under any conditions.

As a case study, the team simulated the forces involved in the 2010 Deepwater Horizon explosion in the Gulf of Mexico, finding that its model accurately predicted the location and propagation of cracks in the oil rig’s drill riser — the portion of pipe connecting the surface drilling platform to the seafloor.

In a side-by-side comparison, the researchers found that their model’s reconstruction closely resembled an image of the actual fractured pipe taken by a remotely operated vehicle shortly after the accident occurred.

While it’s unlikely that any pipe material could have remained intact during the Deepwater Horizon disaster there might be improvements that can be made to reinforce existing oil and gas pipelines.

‘The deeper you go in the ocean, two or three miles down, the stronger material you need to withstand the pressure,’ said project lead Tomasz Wierzbicki of MIT. ’But stronger materials are more brittle and break more easily. So there’s a difficult problem for the offshore industry and I think [it] can learn a lot from us.’