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(Versa Sonic Drill mounted on 2008 Peterbilt 340 6 x 6) (Versa Sonic Drill mounted on 2000 International 4900 6 x 6)
At Frontz Drilling, Inc. our Sonic capabilities include the following:
Sonic drill rigs are more precisely identified as rotary-vibratory drills. At first glance, a Sonic drill rig looks much like a conventional air or mud rotary drill rig. The difference lies in the drill head, which is larger than a standard rotary head. The sonic head contains the mechanism necessary for rotary motion, as well as an oscillator to produce high-frequency force, which is then superimposed onto the drill string. The drill bit is therefore vibrating up and down, as well as being pushed down and rotated. The combination of these forces allow drilling to proceed rapidly through most geological formations, including some types of rock. In overburden, the vibratory action causes the surrounding soil to fluidize, allowing penetration. In rock, the bit causes fractures in the rock face, creating dust and small rock particles, which allows advancement of the bit. In certain cases, the drilling and rock coring can be completed without the use of any drilling fluid. Sonic drilling provides highly representative, undisturbed, continuous core samples, while producing an average of 80% less waste than traditional drilling methods. This includes difficult terrains, even with the presence of boulders. The oscillator is driven by a hydraulic motor, using out-of-balance weights to generate high sinusoidal forces, which are then transferred to the drill bit. An air-spring is also in place to confine the vibratory forces to the drill string. The frequency can be varied to suit operating conditions and is generally 50-120 Hz (cycles per second). In comparison, ordinary household current in many countries alternates at 60 Hz. The frequency range falls within the lower range of sound vibrations that the human ear is capable of hearing. This explains the term "Sonic Drilling" being linked to these rotary-vibratory drill rigs. The principle behind sonic drilling may appear complex, but the machine is actually simple to operate. The driller adds vibratory energy to the normal rotary motion by selecting a frequency that provides the best drilling rate or core recovery, whichever the case may be. The following charts detail some of the many time and cost-saving differences between the different common drilling methods. This information was obtained from the December 2007 issue of GeoDrilling International magazine.
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