Patent ID: 6265355
Filing Date: 2001-07-24
Classification: C09K,Y10S

Abstract:
A gel breaker composition for breaking a gel deposit, positioned in a subterraneous formation and formed by a cross-linkable polymer and a cross-linking agent, the composition consisting essentially of a aqueous solution containing from about 0.01 to about 25 weight percent of the composition of a chelating agent consisting of at least one of phosphonic acids containing at least 3 phosphonate groups and selected from the group consisting of aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra(methylenephosphonic acid), hexamethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid) and triethylenetetramine hexa(methylenephosphonic acid), and phosphino polycarboxylic acid and phosphinomethylated polyamine and from about 0.01 to about 8.0 weight percent of at least one of ethylenediaminetetraacetic acid, disodium ethylene diaminetetraacetic acid, nitriloacetic acid, tetrasodium ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid pentasodium salt.