Abstract: This invention relates to compounds of formulae (1a) and (1b) wherein R means H or C1- to C6-alkyl, X is a structural unit selected from the formulae ?wherein m and k mean independently from each other a number from 1 to 12 for (4) and (5) and from 1 to 11 for (6), Y is a structural unit selected from the formulae wherein a, b independently from each other are integers from 1 to 10 R means hydrogen or C1- to C6-alkyl R2 means an alkylene or alkylidene group having 1 to 6 carbon atoms or an arylene or alkylarylene group having from 6 to 20 carbon atoms R3, R4, R5, R6 independently from each other mean an alkylene or alkylidene group having 1 to 6 carbon atoms or an arylene or alkylarylene group having from 6 to 20 carbon atoms, Z means a cation, and n means an integer being two or higher.

Abstract: This invention relates to a process for inhibiting scaling in a subterranean oil or gas producing formation, comprising adding to the formation a composition comprising a metal chelant, a scale inhibitor and divalent metal cations, wherein the stability constant of the metal chelant—metal cation chelate at ambient temperature is equal to or higher than the stability constant of the chelate formed from the metal cations and the scale inhibitor, and wherein the solubility of the chelate formed from the metal cations and the scale inhibitor decreases with increasing temperature.

Abstract: This invention relates to a process for inhibiting scaling in a subterranean oil or gas producing formation, comprising adding to the formation a composition comprising a metal chelant, a scale inhibitor and divalent metal cations, wherein the stability constant of the metal chelant-metal cation chelate at ambient temperature is equal to or higher than the stability constant of the chelate formed from the metal cations and the scale inhibitor, and wherein the solubility of the chelate formed from the metal cations and the scale inhibitor decreases with increasing temperature.

Abstract: This invention relates to a process for inhibiting scaling in a subterranean oil or gas producing formation, comprising adding to the formation a composition comprising a metal chelant, a scale inhibitor and divalent metal cations, wherein the stability constant of the metal chelant—metal cation chelate at ambient temperature is equal to or higher than the stability constant of the chelate formed from the metal cations and the scale inhibitor, and wherein the solubility of the chelate formed from the metal cations and the scale inhibitor decreases with increasing temperature.

Abstract: This invention relates to compounds of formulae (1a) and (1b) wherein R means H or C1- to C6-alkyl, X is a structural unit selected from the formulae wherein m and k mean independently from each other a number from 1 to 12 for (4) and (5) and from 1 to 11 for (6), Y is a structural unit selected from the formulae wherein a, b independently from each other are integers from 1 to 10 R means hydrogen or C1- to C6-alkyl R2 means an alkylene or alkylidene group having 1 to 6 carbon atoms or an arylene or alkylarylene group having from 6 to 20 carbon atoms R3, R4, R5, R6 independently from each other mean an alkylene or alkylidene group having 1 to 6 carbon atoms or an arylene or alkylarylene group having from 6 to 20 carbon atoms, Z means a cation, and n means an integer being two or higher.