Geothermal Well Drilling
On the third day, the drillers came back to seal the wells, collect all of their equipment, and head home.
Of major importance is sealing the well to prevent any contaminants from getting into the ground water. ne improperly sealed well could allow contaminants to pollute the water of numerous other wells in the area. For this reason, the material that is pulled up while drilling is not placed back in the well. Instead, a special material called "Quick Grout", or sodium bentonite, is put it the well before it is sealed off.
Sodium bentonite is a superabsorbent polymer. When placed in water it absorbs about 10 times its mass and forms a gel-like solid. Filling the well in this manner prevents anything from getting into the groundwater.
The Quick Grout is added to water to form a slurry that is then pumped into the wells where it forms a seal. This is important because it prevents any contaminants from getting into the ground water.