Methods for preparing slurries that include depolymerized polysacoharides and depolymerized and derivatized polysaccharides that may be useful in subterranean well operations including fracturing, gravel packing, and frac-packing, are provided. One embodiment provides a method for making a slurry, comprising combining a polysaccharide with an organic solvent to form a slurry; and, depolymerizing the polysaccharide in the slurry. Another embodiment provides a method of treating subterranean formation with slurry comprising the steps of creating a slurry using a method comprising the steps of combining a polysacchande with an organic solvent to form a slurry; and, depolymerizing the polysaccharide in the slurry; and, placing that slurry into a subterranean formation.