Subsea pipeline welding performed at record depth

It is the first time that hot-tap welding, a way of connecting pipes, has been done at such depths and is the culmination of around 10 years’ research by Cranfield University and industrial partner Statoil.

The work could have a major impact on the offshore gas and oil industries, as Neil Woodward, an engineer for Statoil who is based at Cranfield, explained to The Engineer.

‘Say there’s a pipeline already on the sea bed, it might have been there 20, 30 years and, for whatever reason, it’s more economical to tap into that pipeline and divert a bit of flow somewhere to make the oilfield more profitable, rather than lay a new pipe.

‘It’s called hot tapping because the product is still flowing in the pipe — you don’t close the pipe and that is a big economic driver, because if you have to shut down a pipe you’re potentially talking about millions of pounds a day.’