Abstract: The invention provides for the use of a copolymer, comprising a) 0.1 to 10 mol-%, based on the weight of the copolymer, of structural units derived from vinylphosphonic acid or of a salt thereof, b) 40 to 80 mol-%, based on the weight of the copolymer, of structural units derived from compounds of the formula (1) c) 1 to 50 mol-%, based on the weight of the copolymer, of structural units derived from compounds of the formula (5) in which X is OH or NR3R4, and R3 and R4, independently of one another, are H or C1-C4-alkyl, for the inhibition and/or dispersion of inorganic sulphide scales, and for a process for the inhibition and/or dispersion of inorganic sulphide scales, the process comprising adding to water being within an oil or gas containing formation said copolymer.

Abstract: The invention provides for the use of a copolymer, comprising a) 0.1 to 10 mol-%, based on the weight of the copolymer, of structural units derived from vinylphosphonic acid or of a salt thereof, b) 40 to 80 mol-%, based on the weight of the copolymer, of structural units derived from compounds of the formula (1) c) 1 to 50 mol-%, based on the weight of the copolymer, of structural units derived from compounds of the formula (5) ?in which X is OH or NR3R4, and R3 and R4, independently of one another, are H or C1-C4-alkyl, for the inhibition and/or dispersion of inorganic sulphide scales, and for a process for the inhibition and/or dispersion of inorganic sulphide scales, the process comprising adding to water being within an oil or gas containing formation said copolymer.

Abstract: The invention provides for the use of a copolymer, comprising a) 0.1 to 10 mol-%, based on the weight of the copolymer, of structural units derived from vinylphosphonic acid or of a salt thereof, b) 40 to 80 mol-%, based on the weight of the copolymer, of structural units derived from compounds of the formula (1) c) 1 to 50 mol-%, based on the weight of the copolymer, of structural units derived from compounds of the formula (5) in which X is OH or NR3R4, and R3 and R4, independently of one another, are H or C1-C4-alkyl, for the inhibition and/or dispersion of inorganic sulphide scales, and for a process for the inhibition and/or dispersion of inorganic sulphide scales, the process comprising adding to water being within an oil or gas containing formation said copolymer.

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.