What is Horizontal Directional Drilling (HDD)?
HDD construction involves the following process: • First, a pilot hole is drilled using a steerable drill. The drill’s location constantly checked and adjusted using a transmitter and receiver as it is drilled from the entry to the exit point. Drilling fluids are used and recycled to aid in removing cuttings, as well as stabilising the bore hole. • Next, the pipeline is “reamed” (enlarged) to the required size using a series of reamers. This process may take several stages to reach the desired pipe diameter and maintain borehole integrity. Drilling fluids are again used to remove cuttings and stablise the borehole. • The pipeline is then joined into a continuous length and laid out ready to be installed, then connected to final reamer via a swivel and pulled through the borehole from the exit point to the entry point. Drilling fluids are again used to remove cuttings, stabilise the hole and lubricate the product pipe. Construction time will depend on bore distance, borehole size, geolo
