How Does Horizontal Directional Drilling Work?
There are three main stages in the horizontal directional drilling process: pilot drilling, expanding the drilling point of entry, and pulling the production pipe. Let’s explore each stage in more detail below:

Step 1 - Creating the Pilot Hole
The horizontal directional drill punctures a small diameter hole to create an underground cavity utilizing a drill bit and pipe. Drilling fluid is run through the drill pipe to the drill bit to grind down the soil and rock, cool the drill bit, and carry the cuttings from the hole to the surface.

Step 2 - Pre Reaming
To ensure that the bored hole is large enough to safely install the product lines, a cylindrical rotary cutting tool is pulled back and forth along the pathway while drilling fluid runs through to deepen the hole and remove any remaining rock blocking the passageway.

Step 3 - Pipe Pullback
In the final step, the product pipe is pulled into the drill hole. The drill rod and reamer are attached to a swivel, preventing torsional stress, while the rotating drill string is transferred to the pipe. While the product pipe is pulled into the pre-reamed hole, drilling fluid is pumped throughout the cavity to provide lubrication.