Dale E Nierode, Donald M Kehn, Keith F Kruk: Method of acidizing subterranean formations. Exxon Production Research Company, Robert L Graham, January 27, 1976: US03934651 (27 worldwide citation)

A subterranean formation is treated by injecting into the formation an aqueous acid solution comprising a water soluble vinyl compound (preferably polyvinyl alcohol or polyvinylpyrrolidone), a natural gum (preferably guar gum or gum karaya) and finely divided particulate material (preferably silica ...