Horizontal Directional Drilling is a method of drilling used for laying subsurface pipes and cables without interfering with infrastructure (streets or railways) or harming the environment (e.g. rivers and lakes).
The first step in HDD-Drilling is a controlled pilot hole. Where necessary a reamer is then used for widening the borehole. Finally the cable or pipe is pulled through.
All three steps need an appropriate drilling fluid in order to proceed successfully.
