Cryogenic rehabilitation can be an efficient nontoxic way to rejuvenate a failing water well. The oil industry found carbon dioxide cleaning increased oil production by up to 23%. In water wells the fluid viscosity is much thinner and water yields can often out produce the original production rates.  Pound for pound CO₂ packs as much energy as high explosives and is much safer to use. It is quickly becoming known as the GREEN GENTLE GIANT of water well cleaning.

Solid carbon dioxide known as dry ice has been used in water wells for years. There are many myths, few successes and a lot of unwanted outcomes from dropping dry ice down a water well. Heavier than water ice, dry ice sinks to the bottom where it boils off CO₂ gas. The gas dissolves into water to form carbonic acid, pressured carbonated water. The reaction is just like shaking up a soda bottle, the pressurized bubbly fizzy frothy water rises and shoots out the top. (See picture on left) This may help a small shallow well but most energy is wasted to up-venting creating a cold-water explosion.

Capping the well at the surface confines the cleaning energy. Many a tractor or truck has been overturned by trying to hold down the cap. Welding a lid near the well head contains flyout, but the cold explosive pressure is now focused in the upper well and can freeze. Like placing a soda can in a freezer overnight, it can explode breaking upper casing or damage the surface seal, while leaving the deep-water zone untouched. The biggest danger comes from over cleaning the upper well leading to sand pumping and surface contamination.

Take out the myths, apply science and an isolation packer and carbon dioxide becomes a powerful way to clean a well without toxic chemicals. Started in the oil industry as cold steam injection or hydrofracking, carbon dioxide is used because it vaporizes from a solid to a gas at ­109⁰F and the vapor emitted has 60% more power than water steam. Placing a packer directly above a work over zone and the cold steam travels out and freezes the area around the well. Freezing water expands up to 9% with a hydraulic force that can reach up to 30,000 psi. The pressurized carbonated dioxide pushes out and frees up both the filter pack and aquifer.

Carbon dioxide is an environmentally friendly good way to clean a well, but it is not the only way and can be aided by other processes. Sometimes chemicals or scraping away calcified deposits is needed, and always debris removal and cleanup is important. It is not a fancy name that makes well cleaning work, it’s chemistry and energy applied with pressure that works. With a little knowledge, and the right tools even frozen water can clean a well.