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Notes from the Groundwater Guy by Thomas E. Ballard, P.G., C.H.G. Southeast Hydrogeology, PLLC What Makes an Efficient Well? Part 2 In Part 1, we discussed what well efficiency is and how it is measured - but what can we do to ensure we end up with the most efficient well possible? In general, an efficient well starts with design of the well, but also includes construction factors. Well design considerations include: 1. A proper well screen with sufficient open area to allow for reasonable entrance velocities and reduce the turbulent flow of groundwater into the well; 2. Proper distribution of well screen can enhance the flow of water to the well and reduce turbulent flow and groundwater velocity. Due to the design of the screen open areas, wire-wrap screens will be more efficient than mill slot screens; 3. Sufficient length of screen and penetration of the aquifer will allow for mainly horizontal flow to the well. Any vertical flow component will result in head losses and reduced well efficiency; and 4. Properly sized gravel pack with gravel as spherical as possible to maximize flow into the well screen. Well design considerations are really focused on maximizing horizontal flow of water to the well and minimizing the vertical component which can reduce head losses and enhance efficiency. Reduction of turbulent flow to the well also enhances effi- ciency by reducing load on the pump, as well as reducing other problems such as possible cavitation. Well construction considerations include: 1. Proper well development is a key well construction factor as it has the net effect of increasing the permeability of the formation surrounding the well; and 2. Proper placement of the well screen with respect to the most significant water-bearing zones in the aquifer. As discussed previously, proper well development is one of the most significant factors in not only producing an efficient well, but also in maximizing the capacity of the well. Time and money spent on proper well development gives a significant “bang for the buck” investment in an efficient, quality well, yet it is often one of the most overlooked parts of the well construction process. Proper placement of well screen is a function of conducting an electronic log (elog) of the borehole and performing ade- quate zone testing prior to committing to final well design plans. This allows for proper placement of screen, as well as sizing of screen and gravel pack. While there are a number of considerations which must be taken into account to design and construct an efficient well, the increased capacity and reduced costs of operating an efficient well make the process well worthwhile. Tom Tom Ballard may be contacted via e-mail to michele@worldwidedrillingresource.com The 2019 National DrillingAssociation Convention will be September 26-27, at the Hyatt Regency Dulles in Herndon, Virginia. The event starts with the Annual Joe Scribellito Jr. Memorial Golf Outing at Herndon Centennial Golf Course on Thursday. There is a day excursion planned for those not golfing. Cocktails and visiting with exhibitors is from 5:00- 6:00 p.m., followed by the president’s dinner, award presentations, entertainment, and Chinese raffle. Friday has several presentations for continuing education credits, along with more time to view vendor displays. A meeting of all chapters is set for 4:30 p.m. Go to www.nda4u.com for more information and to register. Where are you planning to go? How about including this show: See more events at www.worldwidedrillingresource.com online issue. New & Used Bits, HDD Bits & Tools, Drag Bits & Wings, Bolt-On Drag Bits, Reverse Circulation Tools, Hole Openers, Claw Bits, Stabilizers, Subs, Custom Tooling & Welding, Hammer Bits, Drill Collars, Pipe Wipers, and Drill Pipe. Office: (661) 834-4348 Rod Henderson / Eran Henderson 661-201-6259 • 661-330-0790 sales@bitcobits.com www.bitcoinc.us 19 WorldWide Drilling Resource ® AUGUST 2019 WTR Join WWDR W