Compositions and methods for the dissolution of iron sulfide

A method of servicing a wellbore disposed in a subterranean formation, the method comprising:

• placing into the wellbore a fluid comprising:
• (i) a biochelant present in an amount from about 10 wt. % to about 70 wt. % by weight of the fluid, wherein the one or more biochelants comprise an aldonic acid, a uronic acid, an aldaric acid, a glucose oxidation product, a gluconic acid oxidation product, a glucarate, a gluconate, glucaric acid, gluconic acid, glucuronic acid, galactonic acid, galactaric acid, or a combination thereof;
• (ii) an organophosphorus compound present in an amount from about 10 wt. % to about 70 wt. % by weight of the fluid, wherein the organophosphorus compound is characterized by a general formula (OR)4P+ [anion] where R is an alkyl group and the anion is monovalent;
• (iii) an enhancing chelant present in an amount from about 5 wt. % to about 40 wt. % by weight of the fluid, wherein the enhancing chelant comprises citric acid, ethylene diamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), hydroxyethylidene diphosphonic acid (HEDTA), methylglycine N,N-diacetic acid trisodium salt (MGDA), N, N-dicarboxymethyl glutamic acid tetrasodium salt (GLDA), 1,10-phenanthroline, acetylacetone, aminomethylphosphonic acid, benzotriazole, benzoylacetone, bipyridine, 2,2′-bipyrimidine, 1,2-bis(dicyclohexylphosphino) ethane, 1,2-bis(dimethylphosphino) ethane, 1,2-bis(diphenylphosphino)benzene, 1,4-bis(diphenylphosphino) butane, 1,2-bis(diphenylphosphino)ethylene, bis(diphenylphosphinoethyl)phenylphosphine, 1,2-bis(diphenylphosphino) ethane, trans-1,2-diaminocyclohexane, 1,2-diaminopropane, tetramethylethylenediamine, 1,1,1-tris(diphenylphosphinomethyl) ethane, ethylenediamine-N,N′-disuccinic acid (EDDS), diethylenetriaminepentaacetic acid (DTPA), hydroxyethyliminodiacetate (HEIDA), 1,2-cyclohexylenedinitrilo tetraacetic acid (CDTA), succinic acid, tartaric acid or a combination thereof;
• and
• (iv) a solvent;
• for a time period sufficient to reduce a level of iron sulfide deposits by at least about 10%,
• wherein the biochelant and the organophosphorus compound are present in a weight ratio of about 1:1.