About Horizontal Directional Drilling (HDD)

Horizontal Directional Drilling

New underground infrastructure construction is an important aspect for a developing municipal environment. Installing this new infrastructure using traditional trenching techniques, particularly open cut construction, can equate to high social costs. These social costs include noise pollution, traffic disruption, aesthetic factors, and negative public perception.  The use of trenchless technologies can enable installation of pipelines and other conduits under these sensitive areas while providing minimal disruption in comparison to traditional trenching methods.

Here are some benefits or directional drilling.

· Less Trenching

· Less Back Filling

· Less Sinking Trench Lines

· Less Reinstatement Cost

· Environmental Friendly

· No Digging Through Water Ways

· No Traffic Disruptions

· No Landscape Violation

Horizontal Directional Drilling (HDD) is a trenchless method of pipe installation. As a trenchless construction method, there are minimum, if any, excavation requirements to install pipe and conduit of varying size and depth. This technique allows for great design flexibility as installation paths, or borepaths, may be curved or straight, with the path changing direction and depth to avoid subsurface obstacles. 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 walk over or wire line 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. To achieve the appropriate bore size it may be necessary to perform several reaming operations. Generally, all reams prior to the actual product installation are referred to as pre-reams, and the final ream to which the product pipe is attached is refereed to as the back ream. The product line is installed once the borehole is enlarged to a diameter that comfortably accommodates the pipe or conduit.

HDD Process