Horizontal directional drilling (HDD) is also referred to as directional boring, a trenchless method used to install underground objects such as cables and pipes using minimal impact. A drilling rig is used to make a shallow radius or arc to make the method practical. This method has lots of advantages when compared to traditional utility installations. Generally, this method describes large boring diameters, maximum drilling rigs, and thousands of feet in crossing lengths. Below is the HDD equipment, technique, and process.
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Horizontal Directional Drilling Equipment
For directional boring to become a success, a few tools are used by the operators. They have several features, and each element has unique benefits. They help the operators to conduct the HDD process successfully. Such tools include
- HDD Milled Tooth Pilot Bits: They enable the operator to drill deep without damaging the components that have sealed the interior due to excess pressure. They have features including a compensation system, greased bearing, hard metal on teeth, and full armor protection. These features increase their benefits; hence they are widely used.
- Small and Medium Diameter Pilot Bits: They are designed for medium-hard developments. They have features such as fluid nozzles, frictional bearing, a large selection of cutting structures, and greased bearing.
- Medium to Large Pilot Bits: They are designed to drill quicker and longer but cut on the cost. They have features including silver plated bearing surfaces, full armor protection package, and industry-proven sealed bearing.
- Random Bit Third Cutters: They lessen the machine’s vibration and allow a deeper penetration compared to the other cutters. Their features include proprietary high load-carrying grease, jet nozzle designs, random cutting structure, among others.
- HDD Bit Kits: Their function is to build cutting tools such as hole openers. Their features include fluid nozzles, a large selection of cutting structures, frictional bearing, and full armor protection.
Some benefits of the features in these tools include;
higher rotational speed bearing capacity,
allowing deeper drilling without damaging grease seals,
prolonged bearing life,
lengthy cutting structure, and integrity,
increased productivity at low cost,
longer-lasting cutting structure for more drilling.
Horizontal Directional Drilling Technique
This technique is preferred because it’s cheaper, quicker, less disruption of traffic, and safe for the environment. It’s used for congested areas, crossing waterways, and environmentally sensitive places. The authorities provide guidelines for this technique so that the operator can’t damage other utilities installed before. It’s favorable in urban areas, especially when fitting subsurface utilities.
It allows a more extended installation at a cheaper cost making it cost-effective. It’s used when only a minimal disturbance is needed. This technique can be used in several pipe materials, including ductile iron, steel, polyethylene, PVC, and polypropylene. Again, it prevents extensive drilling that can damage the underlying utilities. A professional should carry out this technique because careless drilling can damage other utilities.
Horizontal Directional Drilling Process
For the technique to become successful, an inevitable process must be followed. This method involves four stages: drilling the pilot hole, pre-reaming the horizontal boring, pullback operations, and pipes installation. In the end, the operator can achieve the desired path needed.
Stage 1: Drilling The Pilot Hole
The first stage involves the operator drilling a pilot hole horizontally that crosses in the way of the desired path. As to send signals to the receiver, an electronic transmitter is fitted behind the cutting head of the directional drilling. The information is then transmitted back to the drill rig operator, who then determines the designed path.
Stage 2: Pre-Reaming the Horizontal Boring
After the pilot hole is complete, the borehole must be suitable for the product to be installed; thus, it’s enlarged. In this second stage of directional boring, the desired diameters must be achieved. During pre-reaming, a reamer is fitted into the drill string, which is on the opposite side of the borehole. It’s then brought back to the pilot hole by pulling it back. All the boreholes’ cuttings must be flushed out, so slurry is pumped into the borehole to help in the process. This enables the pilot hole to remain clean.
Stage 3: Pullback Operations
In the third stage, a pipe or conduit can be pulled back through the enlarged hole. Prefabrication is done on the pipeline at the drill rig, which is on the opposite side of the borehole. As to connect the reamer to the product, it is fitted to the drill spring using a swivel and a pulling head. The rotating, pullback operation and pulling are enabled by the directional drilling rig on the rotating drilling fluids and the drill string. The pullback operations go on until the pipeline is in the desired place, and then the directional drilling rig enables the reamer to exit the bore path.
Stage 4: Installation of Conduits
After the pipe has been installed, the directional drilling rig helps place the product in the pipe’s desired area. Suppose the horizontally placed conduit is used to carry fiber optic cable or any other products before being pulled into position. In that case, an aircraft cable must be placed before pulling back. As to ensure the effectiveness of the pipe, pressure testing must be done. After this stage, the product lies in the required place in the line, and the installation is a success.
While there are other drilling and utility installations, HDD is preferred because it’s cost-effective despite installing utilities for longer. Again, it can be used in congested urban areas without causing disruptions. To ensure that this technique is a success, the government and other authorities provide that the operator follows specific guidelines. This ensures that the utilities installed before aren’t damaged, and the new installation is correctly done.
This technique is also environmentally friendly, especially in sensitive areas. When installing utilities underground, this technique should always be considered because of its endless benefits. The operators should also be keen to follow the guidelines given to avoid getting into trouble with the law. Industries should consider this technique and process anytime they need to drill and install utilities. This guide provides essential insights about HDD equipment, technique and processes.
