Horizontal Directional Drilling

Horizontal directional drilling is the full technical name for what the industry commonly calls directional boring. HDD projects range in scale from small residential fiber optic installations using mini-rigs to major pipeline crossings of rivers and highways using large maxi-rigs capable of pulling pipe up to 48 inches in diameter or larger.

The HDD process consists of three main phases: pilot bore, reaming, and pullback. During the pilot bore, a small-diameter drill string is steered along the designed path using a walkover or wireline tracking system. The bore is then enlarged to the required diameter using one or more reaming passes. Finally, the product pipe is attached to the drill string and pulled back through the enlarged bore hole.

Hydrovac excavation is integral to HDD operations for exposing existing utilities at crossing points, digging entry and exit pits, and creating access pits for tracking equipment. Many HDD contractors operate their own hydrovac trucks or subcontract hydrovac services as a standard part of their bore operations.