New formulation for pyrite scale removal from oil and gas wells and a method of pyrite scale removal are disclosed. The chemical formulation is composed of K.sub.2B.sub.4O.sub.7-4H.sub.2O, in a concentration of about 9-20 wt. % of the composition, preferably about 14 wt. % of the composition. The new formulation has the ability to dissolve pyrite without generation of the toxic H.sub.2S. Furthermore, the new formulation is cheaper and has very low corrosion rate compare to 15 wt. % HCl with corrosion inhibitor. The disclose method uses the disclosed new formulation to dissolve iron sulphide scale, performed at about 100-150° C. and about 500-2000 psi.

New formulation for pyrite scale removal from oil and gas wells and a method of pyrite scale removal are disclosed. The chemical formulation is composed of K.sub.2B.sub.4O.sub.7-4H.sub.2O, in a concentration of about 9-20 wt. % of the composition, preferably about 14 wt. % of the composition. The new formulation has the ability to dissolve pyrite without generation of the toxic H.sub.2S. Furthermore, the new formulation is cheaper and has very low corrosion rate compare to 15 wt. % HCl with corrosion inhibitor. The disclose method uses the disclosed new formulation to dissolve iron sulphide scale, performed at about 100-150° C. and about 500-2000 psi.

A method of drilling a subterranean geological formation is described. The method includes driving a drill bit to form a wellbore in the subterranean geological formation thereby producing a formation fluid including hydrogen sulfide. The method further includes injecting a drilling fluid into the subterranean geological formation through the wellbore. The drilling fluid includes an aqueous solvent, a hydrogen sulfide scavenger including particles of a manganese oxide supported on a porous support. The particles are suspended in the aqueous solvent. The method further includes reacting the hydrogen sulfide scavenger with the hydrogen sulfide present in the formation fluid to form a manganese sulfide.

A method of drilling a subterranean geological formation is described. The method includes driving a drill bit to form a wellbore in the subterranean geological formation thereby producing a formation fluid including hydrogen sulfide. The method further includes injecting a drilling fluid into the subterranean geological formation through the wellbore. The drilling fluid includes an aqueous solvent, a hydrogen sulfide scavenger including particles of a manganese oxide supported on a porous support. The particles are suspended in the aqueous solvent. The method further includes reacting the hydrogen sulfide scavenger with the hydrogen sulfide present in the formation fluid to form a manganese sulfide.

A method to reduce the deposition of solid sulfur (Ss(s)) in a natural gas producing well, is described wherein the inside of the pipes used in the well are coated with a coating comprising polar surface treated nanoparticles. The polar surface treated nanoparticles interact with the sulfur gas and interfere with the deposition of solid sulfur onto the surface of the pipe. The polar surface treated nanoparticles are selected from the group consisting of silica, alumina and silica-aluminate, metal sulfates and metal oxides.

A method to reduce the deposition of solid sulfur (Ss(s)) in a natural gas producing well, is described wherein the inside of the pipes used in the well are coated with a coating comprising polar surface treated nanoparticles. The polar surface treated nanoparticles interact with the sulfur gas and interfere with the deposition of solid sulfur onto the surface of the pipe. The polar surface treated nanoparticles are selected from the group consisting of silica, alumina and silica-aluminate, metal sulfates and metal oxides.

Solvent mixtures for downhole elemental sulfur removal and formation stimulation, and methods for utilizing such solvent mixtures, are described herein. One method includes providing a solvent mixture that includes an elemental sulfur solvent fraction and an odorant fraction that includes a lactate ester solvent. The method also includes injecting the solvent mixture into a hydrocarbon well such that the elemental sulfur solvent fraction of the solvent mixture dissolves elemental sulfur deposited on well components, and contacting the solvent mixture with water such that the lactate ester solvent within the odorant fraction reacts with the water to generate lactic acid. The method further includes stimulating a formation through which the hydrocarbon well extends by flowing the solvent mixture including the lactic acid through the hydrocarbon well and into the formation.

Solvent mixtures for downhole elemental sulfur removal and formation stimulation, and methods for utilizing such solvent mixtures, are described herein. One method includes providing a solvent mixture that includes an elemental sulfur solvent fraction and an odorant fraction that includes a lactate ester solvent. The method also includes injecting the solvent mixture into a hydrocarbon well such that the elemental sulfur solvent fraction of the solvent mixture dissolves elemental sulfur deposited on well components, and contacting the solvent mixture with water such that the lactate ester solvent within the odorant fraction reacts with the water to generate lactic acid. The method further includes stimulating a formation through which the hydrocarbon well extends by flowing the solvent mixture including the lactic acid through the hydrocarbon well and into the formation.

This invention provides a composition comprising I. at least one reaction product between a nitrogen-free monohydric alcohol and an aldehyde or ketone, and II. at least one reaction product between a nitrogen-free sugar alcohol and an aldehyde or ketone, and optionally III. at least one reaction product from III.a) formaldehyde, and III.b) an amine, selected from the group consisting of primary alkyl amines having 1 to 4 carbon atoms, and primary hydroxy alkyl amines having 2 to 4 carbon atoms, and optionally IV. at least one solid suppression agent selected from the group consisting of IV(a). alkali or alkaline earth metal hydroxides IV(b). mono-, di- or tri-hydroxy alkyl, aryl or alkylaryl amines, IV(c). mono-, di- or tri-alkyl, aryl or alkylaryl primary, secondary and tertiary amines or IV(d). multifunctional amines and IV(e). mixtures of compounds of groups IV(a) to IV(c). wherein alkyl is C.sub.1 to C.sub.15, aryl is C.sub.6 to C.sub.15 and alkylaryl is C.sub.7 to C.sub.15.

This invention provides a composition comprising I. at least one reaction product between a nitrogen-free monohydric alcohol and an aldehyde or ketone, and II. at least one reaction product between a nitrogen-free sugar alcohol and an aldehyde or ketone, and optionally III. at least one reaction product from III.a) formaldehyde, and III.b) an amine, selected from the group consisting of primary alkyl amines having 1 to 4 carbon atoms, and primary hydroxy alkyl amines having 2 to 4 carbon atoms, and optionally IV. at least one solid suppression agent selected from the group consisting of IV(a). alkali or alkaline earth metal hydroxides IV(b). mono-, di- or tri-hydroxy alkyl, aryl or alkylaryl amines, IV(c). mono-, di- or tri-alkyl, aryl or alkylaryl primary, secondary and tertiary amines or IV(d). multifunctional amines and IV(e). mixtures of compounds of groups IV(a) to IV(c). wherein alkyl is C.sub.1 to C.sub.15, aryl is C.sub.6 to C.sub.15 and alkylaryl is C.sub.7 to C.sub.15.