grouting problems

Discussion in 'Geothermal Loops' started by Scoop, Nov 23, 2010.

  1. Scoop

    Scoop New Member

    Hello everyone , thanks in advance for reading and responding to my thread. This is my situation project parameters


    340 ft 5 inch borehole holes in granite
    1,25 inch sdr 11 loop
    grout - bentonite 30 % solids T valve .455

    grout pump dual piston mighty mag 30

    grout mix 50 lbs of bentonite 14 US gallons of water

    grout or temie pipe 1,25 inch black poly line psi rated for 125 psi on air driven reel , spool diameter 34 inches

    water in bore hole 60 ft from surface, water from borehole 200 gpm migrating

    grouting procedure . pump two batches of water to lubricate grout line , push pipe to bottom of hole and begin grout batching and pumping .

    As grout is being pumped pushing the water out of the line the line becomes plugged at 250 to 300 ft in the bore hole . Its like the grout thickens or rather the water gets separated from the solids. The pump spikes in hydraulic pressure and the high pressure relief activates. This pump does not like pumping water

    When trouble shooting this problem we have reduced grout line to 100 ft long removed out of bore hole and the pumping is fine

    Its getting expensive and time consuming changing grout lines as they plug



    WHAT ARE WE DOING WRONG any help would be gratly appreciated
     
  2. GCI

    GCI Member

    RE: grout

    What type of grout are you using? Most standard high solids grouts are designed to be used as 18%-25% solids, not at 30%. To pump at 30% solids concentrations or higher usually requires the use of a thermally-enhanced grouting product.
     
  3. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Ditto,

    Type of grout being used and the "exact recipe" needs to be described. A shot in the dark is that the sand is settling out of suspension down hole in the tremie pipe. I have witnessed this when the wrong grout or recipe is impllemented.
    Eric
     
  4. GCI

    GCI Member

    A standard 30% solids grout doesn't have sand in it.
     
  5. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    My bad,
    long day on the back of the rig,:D Second guess is incorect hydration or retention via polymer. ie grout is developing out prior to exiting the tremie pipe.
    Eric
     
  6. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    14 gallons of water for 50# of grout seems lite on the water.

    What brand and what product grout are you using.

    We use 18 - 20 gallons of water for 50# of BH20 grout from GeoPro.
     
    Last edited: Nov 23, 2010

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