WorldWide Drilling Resource

Environmental Monitoring by Thomas Kwader, Ph.D., P.G. WorldWide Drilling Resource ® Hydrogeologist Well Rehabilitation Using a Surge Block and Treatment Chemicals Many wells produce abundant amounts of clean, clear, good tasting water soon after they are com- pleted. Almost all wells show signs of “age” over time, includ- ing reduced well yields and possibly odors and objectionable taste. New wells are costly and not always an alternative given the location, piping, and land availability. Before you give up on an old well, you may want to try a few “remedies” that may restore the well capacity. Low well yields - a reduction in well yields (gallons per minute or gpm) may be due to: 1) the lowering of water tables in the area which also will lower the pumping rates because of the greater “lift” required to pump the water to land surface; and, 2) plugging of the screen or producing portion of the borehole will cause friction to increase as the water struggles coming into the wellbore. Plugging can occur due to growth of bacteria, iron, lime scale, or other precipitates. There are many fine chemical products available in liquid and granular form that can restore flow through well screens. Many companies will recommend one of their products if you send a sample of material being deposited on your screen. In addition to following the instructions by the manufacturer of the rehabilitation chemicals, I recommend using a surge block, such as Qwater (full disclosure - I invented it!), that firmly fits inside the screen to develop a strong surging action - in and out - of the screen, and out of the formation, allowing the chemical to dissolve the encrustation. Periodic pumping of the well is advised to remove the dissolved precipitates from the well. Repeat soaking and pumping, as long as progress is being made as seen by decreases in drawdown and improved pumping rates. Note, a decrease in pumping rate may also be caused by the pump impellers becoming clogged with precipitates, which can be restored by cleaning the cups of the impellers. Surging should be conducted with a “snug” fitting surge block capable of purg- ing both in and out of the well screen. Tom Tom Kwader may be contacted via e-mail to ENV Simplifying Geotech Operations Adapted from Information by Geoprobe Systems ® Forget the days of herding multiple rigs to a jobsite. Geoprobe ® ’s new 3126GT is a modern-day off-road geotechnical drilling rig that swiftly slides from rotary to automatic drop hammer, even to direct-push or CPT (cone penetration testing), with- out having to reposition the mast or machine. Features include: 1 Hands-free rotary and head feed controls reduce strain on the operator when completing applications like mud rotary 1 Telescoping winch mast with additional height for center rods suited for geotechnical work 1 Wider, larger track base undercarriage for additional ground clearance to tackle difficult terrain 1 Hands-free automatic drop hammer 1 Space to work above the mudpan 1 Outriggers for stabilization 1 More winch capacity to ease auger and spool pulling 1 Centerline head side shift with a GH60 class hammer All this functionality also comes with a smaller footprint, and still includes room for a separate hydraulic circuit for the mud pump to stabilize mud flow, plus space for accessories with two stacked toolboxes, helper-side storage compartments, and control panel storage trays. Atlantis Vault • Self-Contained • Simple installation • Trouble-free operation • Tr For more information call: (270) 786-3010 or visit us online: 32 NOVEMBER 2020 WorldWide Drilling Resource ® C&G