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Grouting & Placement For Geothermal Applications

Grouting & Placement For Geothermal Applications. Presented by Stewart Krause Wyo-Ben, Inc. Billings, MT. Why Grout?. Prevent surface water from entering aquifers. Prevent co-mingling of aquifers. Enhanced Loop Performance Fill All Void Spaces In The Annular Space

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Grouting & Placement For Geothermal Applications

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  1. Grouting & PlacementFor Geothermal Applications Presented by Stewart Krause Wyo-Ben, Inc. Billings, MT

  2. Why Grout? Prevent surface water from entering aquifers Prevent co-mingling of aquifers Enhanced Loop Performance Fill All Void Spaces In The Annular Space Maintain Moisture In The Annular Space

  3. Objective of Grouting: To establish and maintain a seal against all void spaces of equal or lower permeability than that of the least permeable formation intersected. Match thermal properties of the formations to the grouting materials to maximize loop performance & cost.

  4. Typical Grouting & Earth Material Thermal Conductivities Bentonite Grout .40 Neat Cement .55 Dry Bentonite Chips .20 Saturated Bentonite Chips .50 TG85 .85 Dry Sand .20 Saturated Sand 1.40 Heavy Dry Soil .50 Heavy Damp Soil .75 Heavy Saturated Soil 1.40 Average Rock 1.40 Dense Rock 2.00 Ref. Dr. Charles Remund

  5. Soil Thermal Conductivity Ref. VA Dept of Mines & Minerals

  6. Calculating Hole Volumes Hole Diameter Squared Divided by 24.5 = Hole Volume in Gallons per Foot EXAMPLE (4.5 inch Hole) : 4.5 x 4.5 = 20.25 / 24.5=.83 gpf

  7. Product Sheets Listed information should include Mixing ratio Density Thermal Conductivity Product Yield

  8. Commonly Used Grouting Materials Cement Grouts High Solids Bentonite Grouts Thermally Enhanced Bentonite Grouts

  9. Commonly Used Grouting Materials Cement Grouts Available—Easily pumped—Structural—Easily Probed vs. Heat of Hydration—Subsidence—Shrinkage

  10. Cement Grouts Neat Cement Engineered Cement Grouts Mix 111

  11. Cement Grouts Neat Cement 5.2 Gallons Water 94# Type 1 Cement

  12. Cement Grouts Engineered Cement Grouts Bentonite Plasticizers Retardant Accelerators Filtrate Control Sand

  13. Cement Grouts Mix 111 6.19 gallons water 94# Type 1 Cement 21 oz Super plasticizer 1.04# Bentonite Ref. M.L. Allan @ Brookhaven National Laboratory

  14. Commonly Used Grouting Materials High Solids Bentonite Grouts Pumpability—Low permeability—Cost—Flexible vs. Difficult to probe—Subsidence

  15. High Swelling Bentonite • Products Effectively Create Seals • Restricts surface water penetration to lower aquifers • Restricts inter-aquifer mingling and artesian flow • Keeps moisture around sands in the annular area • Fills all void spaces in the annular area

  16. Dispersed • Granular • Powder • Encapsulated • Granular High Solids Bentonite Grouts

  17. Thermal Conductivity .43 to .45 Solids Content 15% 20% 30% High Solids Bentonite Grouts

  18. Calculating Solids Content Grout Weight ÷ (Water Weight + Grout Weight) = % Solids (By Weight) Example: 50 ÷ 250 = .20 or 20% Solids 50 lbs. (Bentonite Grout) 200 lbs. (24 Gallons Water) + 50 lbs. (Bentonite Grout)

  19. High Solids Bentonite Grouts Flowable

  20. High Solids Bentonite Grouts Develops Gels When At Rest

  21. High Solids Bentonite Grouts

  22. With Densities Greater Than Water, High Solids Bentonite Grouts Will Easily Displace Water & Fill Voids

  23. High Solids Bentonite Grout’s Flowable Nature Allow It To Seal Into Voids And Establish An Excellent Bond With All Surfaces.

  24. Commonly Used Materials for Grouting Thermally Enhanced Bentonite Grouts Pumpable—Flexible—Low permeability vs. Some subsidence—Cost—Labor

  25. Thermally Enhanced Grouts Thermal Conductivity .93 @ 200 lbs. Sand 1.20 @ 400 lbs. Sand Solids Content 64% 71%

  26. Thermal Conductivity Testing

  27. Objective Behind Grouting TO ESTABLISH AND MAINTAIN A SEAL AGAINST ALL VOID FACES, WITH AN EQUAL OR LOWER PERMEABILITY THAN THE LEAST PERMEABLE FORMATION INTERSECTED.

  28. Choosing Grouting Material &Equipment • Type Of Grouting Material To Be Placed • Depth To Be Placed • Local Regulations (allow for pulling the temmie pipe or bottoms up) • Specification Requirements (tremmie pipe size limitation)

  29. Equipment

  30. Gear Pump

  31. Progressive Cavity Pump

  32. Piston Pumps

  33. Piston Pumps

  34. Piston Pumps

  35. Site Testing Mud Balance Water Volume Record Keeping Thermal Conductivity

  36. Sealing Boreholes While Utilizing Thermal Energy “Is” Protecting Our Children's Future Wyo-Ben, Inc. Billings, MT

  37. Questions ?

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