In pipeline construction, major crossings are usually installed by Horizontal Directional Drilling. In the Environmental sector this method is applied for installation of horizontal filter wells, for remedation of polluted areas or the recovery of old cables.

A horizontal filter well can be installed by drilling with entry and exit points or as a blind bore hole. The drilling fluid has to meet the required drilling specifications. After installation of the well the annulus breaks down as soon as the biological degradation of the drilling fluid starts. This loosening of the ground helps to increase the permeability in the surrounding of the well.