About HDD
What is HDD?
Horizontal Directional Drilling (HDD) is a trenchless method of pipe installation. As a trenchless construction method, there are minimum excavation requirements to install pipe and conduit of varying size and depth. This technique allows for great design flexibility as installation paths or bore paths may be curved or straight with the path changing direction and depth to avoid subsurface obstacles.
Benefits of HDD
HDD Installation Process
The installation of pipe and conduit utilizing directional drilling is typically completed in a two-phase operation, including the drilling of a pilot hole and its subsequent reaming to install the product pipe. Installation of conduit and pipe is conducted from the surface, and commences with the boring of a pilot bore along the path of installation.
The pilot bore is launched from the surface at an angle between 8 and 20 degrees to the horizontal, and then gradually becomes horizontal when the required depth is reached. The bore can be steered and tracked from the surface using a walkover or wireline locator system to direct the bore to the exit location.
Once the drill string reaches the surface at the exit location, a reamer is attached to the drill string and pulled back to the entry point. This process enlarges the borehole for the installation of the product line. The product line is installed once the borehole is enlarged to a diameter that comfortably accommodates the pipe or conduit.
Resources
Click the links below to find out more about HDD and the Drilling process. Will have Videos listed here for people to watch.