How sonic drilling works
Sonic is an advanced form of drilling which employs the use o high-frequency resonant energy generated inside the Sonic head to advance a core barrel or casing into subsurface formations. During drilling the resonant energy is transerred down the drill string to the bit face at various Sonic frequencies. Simultaneously rotating the drill string evenly distributes the energy and impact at the bit face.
The resonant energy is generated inside the Sonic head by two counter-rotating weights. A pneumatic isolation system inside the Sonic head prevents the resonant energy from transmitting to the drill rig and preferentially directs the energy down the drill string.
The driller controls the resonant energy generated by the Sonic head’s oscillator to match the formation being encountered to achieve maximum drilling productivity. When the resonant Sonic energy coincides with the natural frequency of the drill string resonance occurs. This results in the maximum amount of energy being delivered to the face. At the same time friction of the soil immediately adjacent to the entire drill string is substantially minimied resulting in fast penetration rates.