WorldWide Drilling Resource

70 DECEMBER 2021 WorldWide Drilling Resource ® RENEW - SUBSCRIBE NOW! Check the well components. One of the most common reasons for a drop in water production is the plugging of holes or slots along the well’s casing and encrustations forming on the well screens. Calcium carbonate, silt, clay, iron sulfides, and iron, as well as manganese bacterial biofouling, are all common well cloggers. There may also be a collapse in the well, closing off portions of screens. The screened part of the well allows water to get into the well while reducing or preventing transport of sand and silt, but an improperly sized screen (with slots too large or too small) can allow sediment in the water to clog the well or grit to damage the pump. Some maintenance may be needed to improve the yield. Two typical methods are using chemicals to loosen, and sometimes dissolve, the encrusting materials so they can be pumped from the well or cleaning the well using mechanical action, pressure, or fluid force. The best results come from using both. Chemicals aid in loosening deposits, but actions, such as high-pressure jetting or well surging, finish the task by flushing debris out. Several other options for correcting low-yield wells are available. If the aquifer is low-yielding, then well deepening and lowering of the pump may be required. If the well is an open-borehole well, such as one constructed in bedrock, increased yield may be achieved if the well is hydrofracked. This process of hydrofracking is essentially sealing some portions of the well to increase the pressure inside the borehole, causing the rock to fracture, and consequently, increasing yield. As a remediation technique, it may be prudent and less costly for the well owner to consider water storage to meet peak demand. Talk with them about the possibility of borehole storage or auxiliary water tank storage to meet their needs when water use in the home exceeds the amount of water flowing from the well. But caution them these methods may not be as reliable during severe droughts because well storage and groundwater flow can vary dramatically. If well rehabilitation is needed to restore compatibility between the well and its owner, this may take some time, usually more than one day. In this case, an alternative water supply or scheduling when the owner will be away might be necessary. If rehabilitation is required, before it begins, the contractor needs to understand the construction and structural integrity of the well to know if it is safe to apply flow, pressure, and mechanical force to the well to clean it. This is where a well log or well construction record can be valuable. A low-yielding well is a matter of persistent concern and frustration to well owners. As professional water well contractors, your expertise and guidance in counseling them through the diagnosis and possible rehabilitation will help to alleviate these concerns and ensure satisfied customers. Drilling Professionals cont’d from page 69 WWDR wishes you and your family a safe and happy holiday season!