Methods and systems for acidification of underground formations with treatment fluids containing chelating agents of double operation

摘要

Abstract when used outside the pH range in which the complexation of metal ions occurs normally, the acid aminopolicarboxu00edlicos may moderate the rate of reaction of acid with the mineral carbonates.Methods for the treatment of a subterranean formation may comprise: providing a treatment fluid comprising an aqueous carrier fluid, an acid, and a chelating agent which comprises an acid aminopolicarboxu00edlico,The treatment fluid having a pH below that which the carboxylic acid groups of the chelating agent are substantially protonated and the chelating agent is ineffective to complex a metallic ion; introducing the treatment fluid into a subterranean formation comprising a mineral D And carbonate; reaction of acid with carbonate mineral, such that the acid, at least.Partially consumed and the pH of the elevations of fluid treatment; and since the pH of the fluid treatment rises above a pKa value for one or more of the carboxylic acid groups, a metal ion chelating with chelating agent.