WorldWide Drilling Resource

17 WorldWide Drilling Resource ® NOVEMBER 2013 Drilling Fluid Updates by Ray McLarty Drilling Fluids & Grouts Questions & Answers Question We have three city wells in West Tennessee. All are the same size and depth. One of the wells, the newest at two years old, has a high reading of iron bacteria. When it first comes on, the water has a rusty tint to it. The other two wells have no reading of iron bac- teria and no rusty tint. We did not drill this well, but saw it developed and don’t think it was developed sufficiently. The gallons per minute is lower in this well than in the other two wells. We think there may be a lot of drilling mud still in the well. Could bentonite left in the well cause a higher concentration of iron bacteria buildup? What do you recom- mend we use to redevelop this well? Answer I don’t think you have an iron bac- teria problem caused by drilling mud. I ran this by a couple of people and we all agree we do not think the iron bac- teria reading or the development of iron bacteria in the well could be the result of a bentonite-based material (drilling mud) being left in the well. As far as redeveloping the well, I re- commend you use AQUA-CLEAR ® PFD or equivalent. AQUA-CLEAR ® PFD is a fast-acting, phosphate-free dispersant that does an excellent job of breakdown and removal of drilling mud, sediment, and clays from the well. If you have this problem, redeveloping the well with PFD could increase the flow of the well. For iron bacteria and slime buildup, I recommend AQUA-CLEAR ® AE , which is a liquid blend of NSF-approved acids and acid enhancers formulated to con- trol bacteria slime contamination. Where you have iron bacteria and slime, you usually have scale buildup. For scale treatment and removal, I recommend AQUA-CLEAR ® MGA , an NSF-approved dry acid additive used to remove iron, manganese, and carbonate scale. AQUA- CLEAR ® MGA can be used alone or in conjunction with AQUA-CLEAR ® AE . I am forwarding you spec sheets on all of the above products. They have product description and the application and functions of the products, as well as suggested usage and recommend- ed treatment. Note: AQUA-CLEAR ® products are from the Baroid IDP well rehabilitation product line. Other manufacturers and similar products would be CETCO ® LBA™ , Cotey Chemical WEL-CHLOR , and Design Water Technologies Unicid . The statements and comments in this article are my own and are based on information and references believed to be true and factual. If you have a question or comment on this article, or on bentonite drilling muds, polymers, grouts, or additives, please forward them to me in care of WWDR . Ray Ray McLarty may be contacted via e-mail at admin@ worldwidedrillingresource.com McLarty trans. cont’d on page 18.