Improved gelled acidic compositions and processes for acidifying underground formations

摘要

The gelled acidic compositions comprise an aqueous acid, acrylamide polymers crosslinked with one or more aldehydes and a reducing or a chelating agent. By way of example, 28 % of hydrochloric acid has been gelled with a 70:30 AMPS/acrylamide copolymer crosslinked with formaldehyde in the presence of erythorbic acid. These gelled acidic compositions can be employed for acidifying underground formations.