I have a proposal for 3 wells, each about 275' deep....based on WF GeoLoop software. Some drillers are proposing grouting the entire bore, others are proposing grouting only the top 60 or so feet, since the rest of the way down the pipe will be in water. We do have a high water table, that is roughly 30-40' from finish grade, even during moderate drouts. Will only grouting down 60', with rest of pipe in standing water in the well provide sufficient conductivity? Seems like it would, but I'm wondering why everything I read it seems that grouting 100% of well is the standard operating procedure. Any insights on this would be appreciated.
From a geo perspective grout is simply to ensure good loop contact with surrounding soil. if loop is truely immersed in water grout is unnecessary for geo performance and could in fact lessen heat transfer efficiency. That said (and I'm no water expert), grout in my mind is employed to protect against ground and cross contamination of aquifers and is required by many local and state agencies (though not all). Finally, anyone who has ever heard of an aquifer migrating or drying up may not want to trust that water there now will always be...... Joe
Grouting the entire bore hole is the accepted standard of conduct among proffesionals per IGSHPA guidelines. That being said, grout costs money. If regional regulations due not require grouting the entire bore drillers will meet the local statute. Geo proffessionals will folllow the IGSHPA guidelines. Just for fun to eliminate the question about efficencyies, enter thi info into the software with full bore grout and with partial and see what happens to the bore depth. Eric
