Underreamer Drill Pipe (or Hole Enlargement Drill Rod) is a specialized drilling tool designed to enlarge existing boreholes. It is widely used in geological exploration, mining engineering, oil drilling, and foundation construction, especially when creating larger passages than the initial borehole allows.

Main Features:

1. High Strength and Stability: Typically manufactured using forging or friction welding technology to ensure structural strength and joint stability.

2. Efficient Hole-Enlarging Capability: Can be equipped with various types of roller cutters or underreamer bits that cut through rock or formation materials during rotation, enabling large-diameter drilling.

3. Wide Applicability: Suitable for a variety of geological conditions, including hard rock, soft rock, and coal seams.

4. Wear Resistance: The surface is specially treated to enhance durability and extend service life, making it suitable for long-duration operations.

Application Scenarios:

· Oil Drilling: Used in deep well drilling to enlarge boreholes at specific depths for casing installation or other equipment deployment.

· Geological Exploration: Employed when larger core samples are needed or when preparing larger channels for follow-up operations.

· Mining Engineering: Helps create ventilation holes, drainage holes, and other necessary infrastructure openings in underground mining.

· Foundation Construction: May be used in bridge pile foundation construction and similar projects requiring precise large-diameter drilling.

Example Technical Parameters:

While exact specifications may vary depending on manufacturer and application, typical parameters include outer diameter, inner diameter, length, and pressure resistance. For example:

· Outer Diameter: 89 mm

· Inner Diameter: 65 mm

· Length: 3000 mm

· Pressure Resistance: ≥35 MPa

With its unique design and functionality, underreamer drill pipe plays an essential role in modern drilling operations, significantly improving drilling efficiency and flexibility.