WorldWide Drilling Resource

Notes from the Groundwater Guy by Thomas E. Ballard, P.G., C.H.G. Southeast Hydrogeology, PLLC A Good Drill Log can be one of Your Best Diagnostic Tools One of my first stopping points when trying to figure out what ails a well is the drill log. There can be a lot of clues there as to potential problems in the well, and it is certainly a lot cheaper to review a drill log than it is to jump into a bunch of expensive diagnostic tools. In the past, we always used to think a drill operator’s logs were completed in the bar after about three or four beers, but they have gotten a lot better over the years, for which I am thankful. In the many cases where the drilling contractor may not be around anymore, the information contained on the log may be the sole record of what happened during well drilling and construction. While the well construction details can be extremely useful, we have tracked down a lot of problems over the years just based on a few notes the crew put on the log, in addition to the required well construction information. In one case, we were able to identify issues causing E. coli hits in several wells in a well field, on the basis of one well log noting lost circula- tion zones at approximately the depth of the bottom of the seal, which revealed a conduit along a surface fracture zone that resulted in surface water intrusion into the well. Since this well was located in an area surrounded by septic sys- tems, shallow groundwater impacted by E. coli was finding its way into the wells via the fractures. Ultimately, the answer was to drill new wells with deeper seals. Without those notes on that one drill log, we would have been challenged to find the cause of the problem without an expensive investigation. We typically also like to review the daily reports if they are available, since they can provide additional clues to dri l l ing conditions and other issues which can affect wel l performance. When locating additional wel ls in an area, both the drill logs and daily reports really provide valuable information on drilling conditions to be expected which can affect both the budget and time frame for a project, as well as the drilling contractor ’s bid. Ful l disclosure of known drilling conditions is vital to mini- mizing change orders on a job and get- ting it completed on time. Sometimes we take drill logs for granted, but we should never underesti- mate their value as an initial diagnostic tool for evaluating a well. Tom Tom Ballard may be contacted via e-mail to michele@ worldwidedrillingresource.com 25 WorldWide Drilling Resource ® MARCH 2019 WTR There is in the worst of fortune, the best of chances for a happy change. ~Euripides