Methods and compositions for removing deposits containing iron sulfide from surfaces comprising basic aqueous solutions of particular chelating agents
AssigneeHalliburton Company
InventorLarry D. Martin
Life of this patent
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Abstract
Methods and compositions for removing deposits containing iron sulfide from surfaces with minimal hydrogen sulfide evolution. A composition comprised of a basic aqueous solution of a chelating agent selected from the group consisting of citric acid, oxalic acid, alkylene polyamine polyacetic acids and mixtures of such chelating agents having a pH in the range of from about 8 to about 10 is brought into contact with the deposits for a period of time sufficient for the deposits to be dissolved therein.
Claims47
A method for dissolving iron sulfide deposits with minimal hydrogen sulfide evolution comprising contacting said iron sulfide with a basic aqueous solution of a chelating agent selected from the group consisting of citric acid, oxalic acid, nitrilotriacetic acid, alkylenepolyamine polyacetic acids and mixtures of said chelating agents, said solution having a pH in the range of from about 8 to about 10.
A method for dissolving iron sulfide deposits with minimal hydrogen sulfide evolution comprising contacting said iron sulfide with a basic aqueous solution of an alkylenepolyamine polyacetic acid chelating agent, said solution having a pH in the range of from about 8 to about 10.
A method for removing deposits containing iron sulfide from surfaces with minimal hydrogen sulfide evolution comprising contacting said deposits with a composition consisting essentially of:
- water;
- a chelating acid selected from the group consisting of nitrioltriacetic acid and an alkylenepolyamine polyacetic acid present in said composition in an amount in the range of from about 4% to about 8% by weight of said composition;
- and
- ammonia present in said composition in an amount such that the pH of said composition is in the range of from about 8 to about 10.
An emulsified composition for dissolving deposits containing organic materials and iron sulfide with minimal hydrogen sulfide evolution comprising:
- a basic aqueous solution of a chelating agent selected from the group consisting of citric acid, oxalic acid, nitrilotriacetic acid, alkylenepolyamine polyacetic acids and mixtures of said chelating agents, said solution having a pH in the range of from about 8 to about 10;
- a liquid hydrocarbon solvent for said organic materials;
- and
- an emulsifier selected from the group consisting of oxyalkylated phenols and the carboxylate salts thereof, and castor oil ethoxylated with forty moles of ethylene oxide.
A method of removing deposits containing iron sulfide from surfaces with minimal hydrogen sulfide evolution comprising contacting said deposits for a period of time sufficient to dissolve said deposits with a composition comprised of a basic aqueous solution of a chelating agent selected from the group consisting of citric acid, oxalic acid, nitrilotriacetic acid, alkylenepolyamine polyacetic acids and mixtures of said chelating agents, said solution having a pH in the range of from about 8 to about 10.
A method of removing deposits containing iron sulfide from surfaces with minimal hydrogen sulfide evolution comprising circulating a composition at a temperature in the range of from about 200.degree. F. to about 300.degree. F. over said surfaces containing said deposits for a period of time sufficient to dissolve said deposits in said composition, said composition comprising a basic aqueous solution of a chelating agent selected from the group consisting of citric acid, oxalic acid, nitrilotriacetic acid, alkylenepolyamine polyacetic acids and mixtures of said chelating agents, said solution having a pH in the range of from about 8 to about 10.
A method of removing deposits containing organic materials and iron sulfide with minimal hydrogen sulfide evolution comprising contacting said deposits for a period of time sufficient to dissolve said deposits with an emulsified composition comprised of:
- a basic aqueous solution of a chelating agent selected from the group consisting of citric acid, oxalic acid, nitrilotriacetic acid, alkylenepolyamine polyacetic acids and mixtures of said chelating agents, said solution having a pH in the range of from about 8 to about 10;
- a liquid hydrocarbon solvent for said organic materials;
- and
- an emulsifier selected from the group consisting of oxyalkylated phenols and the carboxylate salts thereof, and castor oil ethoxylated with forty moles of ethylene oxide.
A method of removing deposits containing organic materials and iron sulfide from surfaces with minimal hydrogen sulfide evolution comprising:
- circulating an emulsified composition over said surfaces containing said deposits, said composition being comprised of a basic aqueous solution of ethylenediaminetetraacetic acid chelating agent present in said composition in an amount of about 4% by weight of said composition, heavy aromatic naphtha present in said composition in an amount of about 30% by volume of said composition, castor oil ethoxylated with forty moles of ethylene oxide emulsifier present in said composition in an amount of about 0.5% by volume of said composition, a corrosion inhibitor comprised of a mixture of an alkylpyridine and dibutylthiourea present in said composition in an amount of about 0.1% by volume of said composition and benzotriazole coupling agent present in said composition in an amount of about 0.3% by weight of said composition;
- heating said composition to a temperature in the range of from about 200.degree. F. to about 300.degree. F. while said composition is circulating over said surfaces;
- and
- withdrawing said composition from said surfaces after said composition has circulated thereover for a period of time sufficient to dissolve said deposits.
Dependencies are inferred from the claim text.