WorldWide Drilling Resource

WorldWide Drilling Resource ® 15 JANUARY 2015 Drilling Fluid Updates by Ray McLarty Drilling Fluids & Grouts Questions & Answers Question We are bidding a job for the aban- donment of several old monitoring wells. There are some two-inch wells, but the majority of the wells are either four or six inches in size. We planned on using Hole Plug in the larger wells, but the regulations state the wells must be sealed with a mixable grout that can be pumped from the bottom to the top of the well. Hole Plug or a similar product would be placed in the top two or three feet of the wells. We are, of course, concerned with the cost of the grout due to this being a job up for bid, but we also want a quality product that provides an excel- lent seal in the well. What do you rec- ommend, and what would the cost per bag be for the product? Answer If you have read any of my grout- ing articles over the years, you know I am a big supporter of using HOLEPLUG ® for any well or hole abandonment. The reasons being, the high solids content obtained when using HOLEPLUG ® , the ease of product placement, and the elim- ination of the need for special mixing and pumping equipment to place the grout. However, since a mixable, pumpable grout is specified, I would recommend one of the following two grouts. They are two of the most economical bentonite grouts on the market today, and have the same yield and solids content. QUIK- GROUT ® , a one-step 20% solid bentonite grout; or BENSEAL ® & E-Z MUD ® , the original high-solids (20%) bentonite grout. QUIK-GROUT ® is an easy-to-mix one-sack granular grout. The ease of mixing allows for the use of conven- tional rig equipment for the mixing and placement of the grout. Also, being a granular bentonite material, it increases the mix and placement time over that of powder materials which hydrate and set up rapidly. This allows the drill crew a little longer mixing and placement time. The recommended mixing rate for QUIK-GROUT ® is one 50-pound sack of QUIK-GROUT ® per 24 gallons of mix water, which will yield 26.3 gallons or 3.6 cubic feet of a 20% grout. When using QUIK-GROUT ® or any 20% solids one-step bentonite grout, care should be taken not to overmix the grout. My second product of choice would be the original high-solids bentonite grout BENSEAL ® & E-Z MUD ® . This two-step grout consists of BENSEAL ® , an eight- mesh granular bentonite, and E-Z MUD ® , a PHPA (partially hydrolyzed polyacry- lamide/polyacrylate) copolymer used mainly as a borehole stabilizer to pre- vent hydration and swelling of reactive clay formations during drilling. The mix- ing of BENSEAL ® & E-Z MUD ® grout requires the use of specific equipment, such as a commercial grouter that has a low-shear mixing device (paddle mixer) and a piston, or gear pump. Instructions are as follows: to 24 gallons of fresh mix water, add 9 to 10 ounces of E-Z MUD ® with paddles at high speed. Immediately after adding the E-Z MUD ® , add one 50-pound bag of BENSEAL ® at a rate of one sack every 15 to 30 seconds. Mix grout only as long as it takes to acquire uniform consistency to the grout slurry. Pump the grout through a 1.25-inch trem- ie pipe into the hole without delay. The paddle should be reduced to a moderate speed during placement of the grout. Note: Manufacturer warns when using either of the above grouts, avoid over- mixing and do not use centrifugal pumps. Note: BENSEAL ® , E-Z MUD ® , and QUIK-GROUT ® are Baroid IDP prod- ucts. Similar products to QUIK-GROUT ® wou l d be M- I SWACO SMOOTH GROUT , Wyo-Ben TD-16 ® , or CETCO ® GRANULAR GROUT . Similar products to BENSEAL ® & E-Z MUD ® would be CETCO ® CRUMBLES / INSTA-VIS™ , Wyo-Ben ENVIROPLUG ® NO. 8 / WYO-VIS ® , and M-I SWACO KWIK-PLUG Fine/POLY-PLUS . I have forwarded two distributors to you who can provide you with per bag cost on the above materials. 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 michele@ worldwidedrillingresource.com & ! $ # & # " ! $ # & # & " & ! " & " $ # & & ! & " & & "! " ! & " " ! ! ! !% $ # "! !