Directional drilling, or boring, is commonly referred to as horizontal directional drilling or HDD. It’s a steerable trenchless method of installing underground pipes, conduits and cables in a shallow arc along a prescribed bore path by using a surface-launched drilling rig that has minimal impact on the surrounding area and environment. Directional drilling is utilized when trenching or excavating is not practical. It is suitable for a variety of soil conditions and jobs including road, landscape and river crossings.
Directional boring is used for installing infrastructure such as telecommunications and power cable conduits, water lines, sewer lines, oil lines and product pipelines. This technique has extensive use in urban areas because it helps in avoiding extensive open cut trenches. It also provides less traffic disruption, lower cost, deeper and / or longer installations, shorter completion times and environmental safety.
Horizontal drilling is done with the help of a viscous fluid known as drilling fluid. It is a mixture of water and, and usually, bentonite or polymer continuously pumped to the cutting head or drill bit to facilitate the removal of cuttings, stabilize the bore hole, cool the cutting head and lubricate the passage of the product pipe.
Locating and guidance of the drilling is an important part of the drilling operation, as the drilling head is under the ground while drilling and, in most cases, not visible from the ground surface.