Water Well Rehabilitation with Aqua Freed®

Water Well Cleaning & Restoration Technology

The day a well is installed and developed, it is pumping at its highest efficiency. Over time, it is very common for water wells to experience lost capacity as well as experience a variety of water quality problems requiring some form of well rehabilitation. Most of these problems are a result of fouling material becoming deposited on the surfaces (rock surfaces, gravel pack, well screen) in water environments. Once these deposits become significant, wells and aquifers will experience lost capacity and water quality changes like discoloration, taste and odor problems as well as “unsafe” (Total Coliform Positive) bacterial problems.

It’s also very common to operate a well for years prior to experiencing loss of capacity. With age these lost capacity problems become more frequent and apparent. The increased lost capacity and the need for more frequent well cleaning and rehabilitation treatments is due to the incomplete removal of plugging deposits from prior rehabilitation efforts, thereby not maintaining the original pore volume of the gravel pack, well screen, or fractured formation.

Effective well rehabilitation requires the removal of all deposited material thereby allowing the specific capacity and pore volume to be more completely restored. There are many different strategies and methods used in well rehabilitation, some successful, others less successful. The success in using many of the physical and chemical methods is dependent on the user being able to fully identify the plugging material, or combination of plugging materials and design a specific chemical treatment to dissolve that material. This becomes a daunting task due to the variability of the complex geochemical and microbiological underground environment and the reliance of the user to perfectly design a specific chemical combination required to fully remove the plugging, while not effecting well construction.

Aqua Freed® is broad ranging in its ability to effectively disrupt and remove a wide variety of plugging deposits, in a wide variety of well construction types and materials, offering superior deposit removal and more complete pore volume recovery, without adversely effecting well construction.

See how Aqua Freed® compares to other water well rehabilitation methods.

Before Aqua Freed Treatment
(looking down into well)

after Aqua Freed (looking down water well)

After Aqua Freed Treatment
(looking down into well)

after Aqua Freed (water well screen)

After Aqua Freed Treatment
(view of side wall)

The Aqua Freed® water well cleaning and rehabilitation process uses gaseous and liquid carbon dioxide to restore water wells. Since 1988, the Aqua Freed® process has been used on more than seven-thousand wells worldwide with excellent results. The Aqua Freed® process has been used on a wide variety of wells including vertical wells, horizontal wells, collector wells, directional wells, angle wells and extraction wells, varying in depth from very shallow to very deep wells, from small diameter to large diameter, screened and open hole (fractured formations: limestone, dolomite, granite, sandstone, etc.).

The Aqua Freed® process is more effective at removing deposits from both inside the well screen and the formation surrounding the well, than any other current method in use. The Aqua Freed® process is not an overly aggressive process, while at the same time is very capable of delivering the necessary energy required to be effective in wells constructed using PVC or HDPE wells, without problems.

Aqua Freed equipment

The Aqua Freed® process is the controlled injection of both liquid and gaseous carbon dioxide, as injection pressure and down-hole pressure are monitored to regulate the feed rate safely accepted within the well. The rate and volume of carbon dioxide injected is regulated to assure that the pressures (and energy) going down the well can dissipate into the surrounding formations.

Aqua Freed®s unique effectiveness is due to a combination of carbonic acid, agitation, and localized freezing resulting in superior disruption and detachment of the encrusted and plugging material.  The bulk of the activity is associated with phase changes of the injected CO2. The expansion rate from a liquid to a gaseous state is 570 times in volume. As phase changes occur, from liquid –> solid –> gas, or liquid –> gas, as determined by our controlled injection, energy is released creating agitation.

Gaseous and liquid carbon dioxide contain tremendous energy, described as energy of dissolution, energy of detachment and energy of agitation. This energy results in the detachment, dissolution and removal of sediments and encrustation from the surfaces within the well screen and the surrounding aquifer.

Mechanical Rehabilitation

Mechanical Well Rehabilitation that STI offers include:

  • Wire Brushing
  • Swabbing
  • Simultaneous airlift swabbing
operator performing Aqua Freed treatment

Chemical Rehabilitation

STI can offer chemical rehabilitation with a variety of chemicals commonly used in Well Rehabilitation. However, chemical treatments are generally less effective than Aqua Freed® in the removal of deposited plugging material and therefore only partial deposit removal is often achieved.

The chemicals that are commonly used during chemical well rehabilitation include:
Acids: Hydrochloric, Sulfamic, Hydroxyacetic, Citric, Phosphoric.
Disinfectants: Sodium Hypochlorite, Calcium Hypochlorite.

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