US Patent 7540328 Solid sandstone dissolver

A dry solid composition is disclosed that, when added to an aqueous liquid, provides a slurry that can be used in sandstone acid fracturing. The slurry generates hydrofluoric acid downhole to etch the sandstone fracture faces created. The chemical and physical properties of the composition result in very uneven etching of the fracture faces, enhancing the fluid conductivity of the final fracture. Optionally, inert masking materials may be included in the dry composition, or added to the slurry, to increase the inhomogeneity of the etching and further increase the fluid conductivity.