A cationic surfactant is disclosed. The cationic surfactant has the general formula [Z-D-N(-D.sup.1-NR.sup.1.sub.3+).sub.a(R).sub.2-a][X.sup.?].sub.a where Z is a siloxane moiety or an unsubstituted hydrocarbyl moiety having from 5 to 20 carbon atoms, D is a covalent bond or a divalent linking group, D.sup.1 is a divalent linking group, R is H or an unsubstituted hydrocarbyl group having from 1 to 4 carbon atoms, each R.sup.1 is an independently selected unsubstituted hydrocarbyl group having from 1 to 4 carbon atoms, subscript a is 1 or 2, and each X is an anion. A method of preparing the cationic surfactant is also disclosed.

A cationic surfactant is disclosed. The cationic surfactant has the general formula [Z-D-N(-D.sup.1-NR.sup.1.sub.3+).sub.a(R).sub.2-a][X.sup.?].sub.a where Z is a siloxane moiety or an unsubstituted hydrocarbyl moiety having from 5 to 20 carbon atoms, D is a covalent bond or a divalent linking group, D.sup.1 is a divalent linking group, R is H or an unsubstituted hydrocarbyl group having from 1 to 4 carbon atoms, each R.sup.1 is an independently selected unsubstituted hydrocarbyl group having from 1 to 4 carbon atoms, subscript a is 1 or 2, and each X is an anion. A method of preparing the cationic surfactant is also disclosed.

Anti-bit balling drilling fluids and methods of making and using drilling fluids are provided. The anti-bit balling drilling fluid contains water, a clay-based component, and at least one of a surfactant having the formula: R(OC.sub.2H.sub.4).sub.xOH, where R is a hydrocarbyl group having from 10 to 20 carbon atoms and x is an integer from 1 and 10, or a polyethylene glycol having the formula: H(OCH.sub.2CH.sub.2).sub.nOH, where n is an integer from 1 to 50. Methods of making and using these drilling fluids are also provided.

Spacer fluids include an emulsion, a surfactant package, and at least one additive that modifies the rheology of the spacer fluid, the density of the spacer fluid, or both. The emulsion may include an aqueous external phase and a hydrocarbon-based internal phase. The surfactant package may include one or more surfactants. The surfactant package may also include a surfactant having the general structure R(OCH.sub.2CH.sub.2).sub.9OH, where R is a hydrocarbyl having 12 carbon atoms, 13 carbon atoms, or 14 carbon atoms. The spacer fluid may contain at least 4.25 pounds of R(OCH.sub.2CH.sub.2).sub.9OH per barrel of the spacer fluid.

Spacer fluids include an emulsion, a surfactant package, and at least one additive that modifies the rheology of the spacer fluid, the density of the spacer fluid, or both. The emulsion may include an aqueous external phase and a hydrocarbon-based internal phase. The surfactant package may include one or more surfactants. The surfactant package may also include a surfactant having the general structure R(OCH.sub.2CH.sub.2).sub.9OH, where R is a hydrocarbyl having 12 carbon atoms, 13 carbon atoms, or 14 carbon atoms. The spacer fluid may contain at least 4.25 pounds of R(OCH.sub.2CH.sub.2).sub.9OH per barrel of the spacer fluid.

An acid corrosion inhibitor includes an active corrosion intermediate including alkylated pyridine, an internal intensifier including formic acid, a filming additive including cinnamaldehyde, a surfactant including one or more of propylene glycol methyl ether and alcohol ethoxylate, and a solvent including ethylene glycol. A system includes a formulation, an acid system including HCl and MSA, and a metal surface contacting the formulation and/or the acid system. The formulation of the system includes an alkyl pyridine, formic acid, cinnamaldehyde, and one or of propylene glycol methyl ether and alcohol ethoxylate. A method for reducing corrosion of a pipe in contact with an acid system and disposed in a well bore includes applying the acid corrosion inhibitor. The acid system includes methanesulfonic acid.

An acid corrosion inhibitor includes an active corrosion intermediate including alkylated pyridine, an internal intensifier including formic acid, a filming additive including cinnamaldehyde, a surfactant including one or more of propylene glycol methyl ether and alcohol ethoxylate, and a solvent including ethylene glycol. A system includes a formulation, an acid system including HCl and MSA, and a metal surface contacting the formulation and/or the acid system. The formulation of the system includes an alkyl pyridine, formic acid, cinnamaldehyde, and one or of propylene glycol methyl ether and alcohol ethoxylate. A method for reducing corrosion of a pipe in contact with an acid system and disposed in a well bore includes applying the acid corrosion inhibitor. The acid system includes methanesulfonic acid.

Methods and compositions for enhancing wellbores and propped fractures for use in geothermal operations are provided. In some embodiments, the methods comprise: drilling with a drilling composition at least a portion of a first wellbore, wherein the drilling composition comprises a base fluid, a resin, and a thermally conductive filler; introducing a fracturing fluid into the first wellbore at a first pressure sufficient to create at least a first set of fractures extending from and in fluid communication with the first wellbore; and introducing a first plurality of proppant particulates into at least the first set of fractures, wherein a second wellbore penetrates at least a second portion of the subterranean formation, and wherein a second set of fractures extends from and is in fluid communication with the second wellbore into the subterranean formation, and the first set of fractures is in fluid communication with the second set of fractures.

Methods and compositions for enhancing wellbores and propped fractures for use in geothermal operations are provided. In some embodiments, the methods comprise: drilling with a drilling composition at least a portion of a first wellbore, wherein the drilling composition comprises a base fluid, a resin, and a thermally conductive filler; introducing a fracturing fluid into the first wellbore at a first pressure sufficient to create at least a first set of fractures extending from and in fluid communication with the first wellbore; and introducing a first plurality of proppant particulates into at least the first set of fractures, wherein a second wellbore penetrates at least a second portion of the subterranean formation, and wherein a second set of fractures extends from and is in fluid communication with the second wellbore into the subterranean formation, and the first set of fractures is in fluid communication with the second set of fractures.

Anti-bit balling drilling fluids and methods of making and using drilling fluids are provided. The anti-bit balling drilling fluid contains water, a clay-based component, and at least one of a surfactant having the formula: R(OC.sub.2H.sub.4).sub.xOH, where R is a hydrocarbyl group having from 10 to 20 carbon atoms and x is an integer from 1 and 10, or a polyethylene glycol having the formula: H(OCH.sub.2CH.sub.2).sub.nOH, where n is an integer from 1 to 50. Methods of making and using these drilling fluids are also provided.