Have you ever been driving along in your car and had the unpleasant experience of your tire popping? I dare say that you were surprised at the sound and power of the small explosion. That came from only about 50 to 75 pounds per square inch (PSI) of pressure.
In the previous page on Hammer Drilling, we explained how hard rock formations are best drilled by using 350 PSI with 750 Cubic feet per minute (CFM) of air – or more!
In South West Colorado, a majority of the drilling takes place in shale. Shale is a soft rock trying to turn into a hard rock with compression and time. Generally, there are not water bearing aquifers in shale. Water works its’ way through shale in tiny little cracks known as fissures. When a borehole is drilled, everyone is hoping that the borehole intersects many of these little fissures of water.
Think of the power and force that is created by hammer drilling. Hammer drilling through shale is like drilling through butter. This is the most profitable drilling that any driller does. At Justice Water Systems, Inc. we will not drill through water bearing shale with an air hammer to try and find water.
Our second objective in our Core Compass guide is to “Create Benefit”. When a driller blasts his way with an air hammer through your shale that may vary in its consistency, the power of the air combined with the flat face of the hammer bit compresses the ground material radially just below the ground being drilled. This compression will close the tiny fissures that would have been providing water for your borehole. But let’s say that a fissure remains open. As the hammer bit drills past the fissure it is forcing the cuttings around the bit and up the borehole to be discharged. But how many of the cuttings have just been impacted into that remaining fissure with high pressure air? Will the fissure have enough pressure behind it to clear itself and flow water into the borehole at some future time?
The combination of the problems with hammer drilling in soft ground gets worse in another situation. Quite often the best quality of water is nearer to the surface of the ground. But it does not have much pressure since it’s not very deep. So if a driller uses hammer drilling to blast the hole, compress the ground, and plug the fissures with the cuttings, of course you’re not going to get any of the good quality water higher up in the formation that is often available. This is a win-win for unscrupulous drillers. They don’t see any water so they have to drill a deeper hole where they make more money – and you pay the bill not only in the cost of the deeper hole, but with costs of water treatment – forever! No Justice at all.
This is a picture of a PDC Bit . . .
NOW, let’s explore Low Pressure Foam Drilling (LPFD). We use a tri-cone or a diamond tipped scraper (A PDC) drill bit at the end of the drill pipe. The drill string turns and spins the bit. The three rollers at the end of the bit either grind up or the PCD bit scrapes the soft shale or clay, while the small amount of air, foam and water is pushed through the center of the drill string where it mixes with the ground up cuttings. The air/foam/water mix carries the cuttings to the surface. The bore hole is continually being washed as it is being drilled. The air pressure we end up forcing down the hole usually less than 75 PSI. There is little to no ground compression from the drill bit. The fissures are much more likely to remain open.
Aspen Springs in Pagosa Springs, much of Durango, and most of Bayfield has soft clay based ground that really should have the Low Pressure Foam Drilling.
And the bonus round is that quite often, we can find a small amount of good quality water not near as deep as the surrounding wells. You spend less money for less depth of well, and you quite often get better quality water . . . all because you’ve had Justice Water Systems, Inc. remain true to our Core Compass – create benefit!
What other knucklehead well-driller takes the time to wash his gravel?