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t’s called ‘horizontal directional drilling’ and we do

it muchmore often thanmany people realise. For

example to pull pipes or glass-fibre cables under a

dike or canal, or to connect wind farms at sea to dry

land. You can also relieve pressure on busy roads by

not digging, and drilling under them. On top of that, if

necessary, we can drill straight throughmountains, as

in Brazil and Colombia. And, closer to the poles, we even

drill in frozen ground to install pipelines. But the biggest

challenge is to drill longer distances in loose soil.

What is so special about horizontal

directional drilling?

‘Themain thing is that we can drill ever longer distances.

Drilling fluid is used to remove the loose soil and to stop

the borehole collapsing. The further you drill, the more

pressure you need to maintain the flow of drilling fluid

from the drilling head to the opening of the hole. The

challenge with horizontal directional drilling is to keep

the drilling fluid moving without the pressure getting

too high. You can blow the whole thing up before you

know it.’

Why are the Dutch so good at this?

‘Horizontal directional drilling emerged in the oil

industry in the USA and then it made its way to

Europe. More knowledge was needed to drill longer

distances. Dutch contractors played a major role in

developing that knowledge. They came up with the

right research questions, shared their observational

It would be a major step forward if we no longer needed to shut

off roads to install new pipelines and cables. We are making

considerable progress thanks to an improved understanding of

how drilling fluids work. Geotechnical consultant Henk Kruse:

‘Some amazing things happen below the surface during drilling.’