How Much Compressor CFM for Borewell Drilling? Annular Velocity & Torque Estimator
Technical Calculator for DTH Drilling Rig Efficiency & Hole Cleaning
🌪️ Air Dynamics & Torque Report
| Calculated Up-Hole Velocity: | ft/min |
| Required Drilling Torque: | Nm |
| Hole Cleaning Status: |
*Optimal cleaning usually requires velocity between 3,000 – 5,000 ft/min for water well drilling.
Above Borewell and Drilling online software defines the air velocity.
DTH Hammer & Compressor Matching Chart
| Hammer Size (Inches) | Recommended CFM | Pressure (PSI/Bar) |
|---|---|---|
| 4″ Hammer | 350 – 450 CFM | 150 – 250 PSI |
| 6″ Hammer | 600 – 750 CFM | 250 – 350 PSI |
| 8″ Hammer | 900 – 1100 CFM | 350+ PSI |
Borewell Drilling: CFM & Air Velocity FAQ
Q: Why is CFM more important than PSI for deep borewells?
Ans: While PSI (Pressure) operates the DTH hammer, CFM (Volume) is what functions to lift the heavy rock cuttings to the surface. If the CFM is too low, the cuttings will fall back into the hole, leading to “regrinding” and potentially causing the drill bit to get stuck.
Q: How does drill pipe diameter affect air velocity?
Ans: It is all about the “Annular Space.” Using a larger drill pipe in a narrow hole decreases the annular gap, which increases the air velocity. This makes it much easier to clear the hole of debris, though it does require more torque from the rotation head to turn the heavier drill string.
