Composition and method of stimulating subterranean formations

A method of acidizing a subterranean formation comprising:

• contacting said formation with an aqueous acidic composition comprising a non-oxidizing acid present in an amount of from about 1 to about 40 percent by weight and a sequestering agent comprising an admixture of (i) at least one member selected from the group consisting of hydroxylamine hydrochloride, hydroxylamine hydrobromide, hydroxylamine sulfate, hydrazine monohydrochloride, hydrazine dihydrochloride, hydrazine sulfate, hydrazine monobromide, hydrazine dibromide, hydrazine monoiodide, hydrazine diiodide and hydroquinone together with (ii) at least one member selected from the group consisting of gluconodeltalactone, isomers of gluconodeltalactone, citric acid, salts of citric acid, ethylenediaminetetraacetic acid, salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, salts of nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, and salts of hydroxyethylethylenediaminetriacetic acid and (iii) a catalytic amount of a solubilized salt of a compound capable of providing at least one member selected from the group consisting of cupric, cuprous, nickel or zinc ions, said sequestering agent being present in said aqueous acidic composition in an amount sufficient to sequester at least a portion of any ferric iron present.

A method of fracturing a subterranean formation comprising:

• introducing into said formation a substantially non-acidic aqueous fracturing composition at a flow rate and pressure sufficient to produce at least one fracture in said formation, said fracturing composition comprising an aqueous fluid and a sequestering agent comprising an admixture of (i) at least one member selected from the group consisting of hydroxylamine hydrochloride, hydroxylamine hydrobromide, hydroxylamine sulfate, hydrazine monohydrochloride, hydrazine dihydro-chloride, hydrazine sulfate, hydraxine monobromide, hydrazine di bromide, hydrazine monoiodide, hydrazine diiodide and hydroquinone togehter with (ii) a catalytic amount of a solubilized salt of a compound capable of providing cupric, cuprous, nickel or zinc ions, said sequestering agent being present in an amount sufficient to sequester at least a portion of any ferric iron present.

A method of fracturing a subterranean formation comprising:

• introducing into said formation an acidic aqueous fracturing composition at a flow rate and pressure sufficient to produce at least one fracture in said formation, said fracturing composition comprising an aqueous fluid and a sequestering agent comprising an admixture of (i) at least one member selected from the group consisting of hydroxylamine hydrochloride, hydroxylamine hydrobromide, hydroxylamine sulfate, hydrazine monohydrochloride, hydrazine dihydro-chloride, hydrazine sulfate, hydrazine monobromide, hydrazine dibromide, hydrazine monoiodide, hydra zine diiodide and hydroquinone together with (ii) at least one member selected from the group consisting of gluconodeltalactone, isomers of gluconodeltalactone, citric acid, salts of citric acid, ethylenediaminetetraacetic acid, salts of ethylenediaminetetraacetic acid, nitrilotriacetic acid, salts of nitrilotriacetic acid, hydroxylethylethylenediaminetriacetic acid and salts of hydroxylethylethylenediaminetriacetic acid and (iii) a catalytic amount of a solubilized salt of a compound capable of providing cupric, cuprous, nickel or zinc ions, said sequestering agent being present in an amount sufficient to sequester at least a portion of any ferric iron present.