Directional Drilling - Frequently Asked Questions
Directional Drilling, is a 'relatively new' trenchless application. Adapted from the vertical well of the oil and gas industry, Horizontal Directional Drilling (HDD) has been a popular installation method for over twenty years. A great low impact method, with an industry of manufacturers constantly evolving their product. HDD is becoming synonymous with trenchless design. Need a visual to help round out your understanding? Check out our Directional Drilling Gallery.
Is a trenchless process whereby a series of rods are ‘piloted’ into the ground and guided along abore path with electronic tracking equipment providing real time roll, pitch, depth and azimuth information. The rods can be directed left, right, up and down to ensure line and grade accuracy. At the conclusion of the pilot bore, the bore path is enlarged by a reaming process. The carrier pipe is then pulled back once the reams have prepared the soil to except the carrier pipe.
HDD is often sought as an alternative for many trenchless installations where soils can not be de-watered or the lengths are great and carrier diameter reasonable. In boulder or dense cobble till grounds, mixed face SBUs may be an alternative.
Key considerations for a successful design include:
- a good geo-techincal report, (cobbles and dense gravels are not ideal soils)
- sufficient righ-of-way for staging the equipment and carrier pipe
- access to potable water for drilling fluid development