Boring, Sampling & Testing Rigs and Equipment
Sonic technology uses high frequency mechanical oscillations, developed in a special drill head, to transmit resonant vibrations and rotary power through the drill tooling to the drill bit allowing it to achieve exceptional penetration rates without the need for drilling fluids or air to effectively take overburden core samples. This is accomplished by the oscillator's conversion of centrifugal force generated by counter rotating, chambered rollers to sinusoidal or longitudinal force. Frequencies in excess of 180 Hz (as previously mentioned) are generated. These frequencies match the natural frequency of the tooling, causing no dampening of the vibratory wavelength to the bit. Therefore, this sonic vibratory action fluidizes the soil particles, destroying the shear strength and pushing the particles away from the tip of the bit and along the sides of the drill string. This liquefaction process allows for clean, rapid and smooth penetration of overburden formations. This unique methodology allows the machine to perform overburden and even bedrock core sampling with speed, precision, and an absolute minimal amount of disturbance and compaction that cannot be accomplished by any other equipment.
One of the main advantages of sonic technology is its superior ability to produce continuous core samples of both unconsolidated and consolidated formations with significant detail and accuracy. The core samples can be analyzed to provide a precise and detailed stratigraphic profile of any overburden condition including dry or wet saturated sands and gravels, cobbles and boulders, clays, silts and hard tills. Recovery of a sample is as consistently close to 100% as any other boring methodology.
The sonic rig also utilizes a dual line of drill pipe. The inner string of drill rods has the core barrel(s) attached. All overburden core sampling is done ahead of the outer string of drill casing with no fluid or air added to insure accurate, representative, undiluted samples. After the core barrel has been advanced, the outer drill casing is advanced to the same depth. This can best be accomplished with water; however, dry casing advancement methods can also be employed and are often performed by Bowser-Morner. With the outer casing left in place to hold the hole open, the core barrel is then removed from the borehole. The core sample can then be extracted into plastic sleeves, stainless steel sample trays, wooden core boxes or virtually any container. The outer drill casing ensures there is no sample contamination from uphole material by sealing it off prior to each sample run.
Also, when water use is permitted for casing advancement, it is by far the quickest and most effective means of combating heaving sands without the use of drilling mud or bentonite.
The outer casing also serves to hold the borehole open for installation of monitoring wells, piezometers, vents, observation wells, instrumentation or other downhole equipment. The outer drill casing has nominal diameters of 6" and 8", allowing ample space to install 2" and 4" wells with a 1" or 1 1/4" tremie pipe to place sand packs, seals, slurries and grouts into the annular space between the well screen/riser and the outer casing and borehole annulus. The drill bits used on the outer drill casing are open and are 5 7/8" through 8 1/2" diameter depending on borehole size requirements.
Another unique feature of the sonic technology method is the ability to ensure the filter pack and bentonite chip or pellet seal can actually be compacted into the borehole annulus by the resonant vibration applied to the outer casing as it is extracted from the borehole with the well screen and riser, pack, seal and grout or slurry installed in the annular space. The vibratory effect makes 'bridging' unheard of and virtually eliminates the potential problem of locking the well and pulling it back as the outer casing string is extracted. This positive placement of well backfill materials allows for very controlled and quick well installations. Coupled with the lack of cuttings slurry, such as in auger drilling, this positive placement greatly reduces well development time and increases well yields.
As required, sonic technology can retrieve thin wall (Shelby) or lined split spoon samples for lab analysis. Another feature is the ability to vibrate a two-inch drive point screen on the end of drill rods with an inflatable packer to seal off the casing. Then, a submersible pump can be lowered in the drill rods to evacuate x volumes of water before collecting a water sample.
Other features of the sonic rig are:
It can be set up for conventional air coring;
It can penetrate hard bedrock by conventional air rotary or downhole hammer methods;
It can also be operated as a straight fluid rotary machine;
It can core through rocks and boulders and most bedrock formations;
Due to the liquefaction principal, it produces a fraction of the drill cuttings and fluids that other methods produce.
The speed, efficiency, superior sampling procedure, depth capacity, safety, reduction of drill cuttings and fluids, and the versatility of the Sonic machine make it a very cost effective and productive way of drilling, sampling, and installing.
Applications include environmental borings, installation of monitoring wells, aggregate exploration (ideal with the large diameter sample to significant depths), rock exploration, methane probes, conductor casing installation, extraction wells, instrumentation and virtually any other application < 12" in diameter and 500' in depth. We have also set up the Sonic for angle borings up to 45. Our Sonic Rig can advance a borehole up to 18" in diameter with some modifications, such as fabrication of an appropriate-sized trash barrel, customized rod make up/break-out, etc.
With the addition of Sonic Technology, Bowser-Morner has acquired the latest technology to the subsurface industry and shown its 'commitment to excellence' once again in meeting customers' needs.
For help with your sonic technology needs, contact us today.
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