HDD Back Reamer / Hole Opener – Operating Conditions & Applications

The HDD back reamer (hole opener) is deployed after the pilot borehole is completed. During backreaming, it enlarges the pilot borehole in stages. Driven by rig torque and pullback force, together with mud circulation, it cuts and breaks the formation, transports cuttings, and finally creates a stable borehole for pipeline pullback.

The HDD back reamer serves as a core tool for trenchless horizontal directional drilling. It enables underground pipeline installation beneath obstacles without surface excavation.

Typical crossing scenarios: rivers, lakes, highways, railways, airport runways and heritage protection zones, avoiding extensive excavation and surface damage.

Barrel Reamer Suitable for sand and soft soil formations with good borehole stabilization performance. It features a thickened cylindrical steel barrel body, with tapered carbide reaming teeth welded on the outer surface of the barrel. Mud jet nozzles are reserved on the barrel wall. The barrel squeezes the borehole wall to reduce borehole collapse risk. Connection subs are fitted at both ends: the front end connects to the drill pipe, and the rear end can be connected to a swivel. Wear bands are hardfaced on the surface to provide wear resistance and protect the barrel body.