First, a small diameter pilot hole is drilled along a directional path from one surface point to another. ĭirectional boring/HDD is generally accomplished in three principal phases. Directional boring can be utilized with various pipe materials such as PVC, polyethylene, polypropylene, ductile iron, and steel provided that the pipe's properties (wall thickness and material strength) enable it to be both installed and operated (if applicable) under acceptable stress limits. Directional boring and HDD are similar in some respects to directional drilling associated with the oil industry, however, an equal comparison cannot be drawn as the procedures serve markedly different functions. Generally, the term Horizontal Directional Drilling (HDD) is intended to describe large/maxi sized drilling rigs, large diameter bores, and crossing lengths in terms of thousands of feet. The term "directional boring" or "bore" is generally reserved for mini/small sized drilling rigs, small diameter bores, and crossing lengths in terms of hundreds of feet. Īlthough often used interchangeably, the terms directional boring and horizontal directional drilling are distinct in that they convey a different sense of scale. The technique is routinely used when conventional trenching or excavating is not practical or when minimal surface disturbance is required.
Directional boring offers significant environmental advantages over traditional cut and cover pipeline/utility installations. The main functions of the fluid are to blend with the soil cuts produced during the drilling process and transport them to the entry pit, to mantain the tunnel stabilized and to lubricate the drilling tip.Method of installing underground utilitiesĭirectional boring, also referred to as horizontal directional drilling ( HDD), is a minimal impact trenchless method of installing underground utilities such as pipe, conduit, or cables in a relatively shallow arc or radius along a prescribed underground path using a surface-launched drilling rig. Typically this system contains a storage tank with fluid reserves to guarantee a constant supply of fluids to the drilling process. Drilling fluids system: Consists on a bentonite, polymer and wáter mixing pump, which injects the fluid trough the drilling pipes all the way to the drilling tip.The operator of the tracker can visualize the information emitted by the probe in real time so it can help the dirlling rig’s operator to make decisions on the directional alingment of the drilling and continue with the correct route, previously planned. Guidance system: It consists of an emitter probe and a walkover tracker, which function is to receibe information on surface and retrasnmit it to a screen located at the drilling rig.In addition, the sonde housing is preceded by the drill tip, which function is to cut the terrain and advance with the directional drilling thanks to its asimetrical shape. The drill pipes are preceded by a sonde housing wich contains an electrical probe that transmits in real time the depth, inclination and orientation of the drilling head, as well as other important parameters.