48 MAY 2025 WorldWide Drilling Resource® What is Well Rehabilitation? Adapted from Information by JKA Well Drilling & Pumps You may have heard about well rehabilitation, or well rehab, but what is it? Well, it can mean a few different things, from a simple well cleaning to a full acidization and biocidal treatment. In general, a well rehab involves brushing and bailing a well to remove buildup of debris along the casing walls and the bottom of the well. Then the well is chlorinated and either surge developed or air lifted to help reestablish production. Well Cleaning typically involves using wire or plastic-bristle brushes and specialized tools to remove debris, called bailers. The wire brush is used to break up and loosen material built-up along the casing walls. Bailers are then run down the well to scoop up the material from the bottom of the well. Surge Blocking uses blocks slightly smaller than the inner diameter of the well to surge water in and out of the well perforations/screen slots as the surge block is cycled up and down in the well, in short 1- to 3-foot strokes. Fine-grained sediment is shook loose and pumped or moved through the open area in the well with a bailer, pump, or airlifting tool after completion of surge blocking. Surge blocks are also used to disperse chemicals, to re-sort the formation around the screen/perforation, and breakup any material encrusted in screen zones or perforations. Air Lifting uses compressed air delivered down the well at high enough volumes to lift water out of the well. It can be used to help remove small debris and contaminants and wash the well casing down. It is also helpful when developing sand screens and perforations, but it isn’t as effective as surge blocking or dual swab air lifting. Dual Swab Airlifting combines the best elements of air lifting with surge blocking. A dual block surge block is lowered on a large pipe to the screen or perforation zone, then a smaller diameter air line is lowered into the well. The air line is energized to create a lifting action inside of the larger pipe. As the surge blocks are raised and lowered in the screen zone, they create a surging action, which displaces fine material that is sucked up by water moving into the larger pipe, which is then airlifted out of the well. Chemical / Acid Treatment can be used for well rehabilitation. These specially designed chemicals and/or acids will remove biofouling, mineral incrustation, and other blockages, while also killing any bacteria, such as iron bacteria, which can create sludge or plug perforations in the well. Careful design of the chemical treatment process is required to make sure the applied chemical is carefully and correctly used, as the chemical costs are often very high, and the work is often time intensive to accomplish correctly. Well Fracturing uses a drill rig or other equipment to place inflatable packers in a well to isolate rock fractures to produce water. Water is pumped into the well below the packers against the rock fractures, often at up to 30-50 gpm (gallons per minute) under 1000-3000 psi of pressure. Remember, this is NOT the same process as hydraulic fracturing used in the gas and oil industry. It’s similar to a high-flow pressure cleaning of the rock fractures. This high-flow cleaning loosens debris and other blockages from the fracture to allow water to enter the well easier. For residential and small irrigation wells, well rehab is performed when the production has dropped to a point where there are interruptions in service, or when a pump fails and it is determined the well has been infilled with material or is severely clogged. At this point, production is so greatly hampered there’s no question as to the value of cleaning and rehabilitating the well. Just like marginal wells with problems, industrial, commercial, municipal, and agricultural wells will benefit from periodic and regular well cleaning, which will increase well performance as well as reduce operating costs. WTR Wondering how to get noticed throughout this magazine? Have your logo stand out (receive an online link too) by merely having us place it wherever we have an empty spot. A really reasonable way to make a splash. Call 850-547-0102 for details.
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