Well Sealants Sodium bentonite sealants in the form of chips (Bentonite Plug), granules (Granular Seal), and powder (Bentonite Grout) are often used to grout/seal well casings or abandon wells. When bentonite is poured or pumped in around a well casing, the groundwater in the well hydrates the bentonite chips or granules, allowing them to swell and form an impermeable seal.
