Multifunctional hydrogen sulfide scavenger

Abstract

The present disclosure is generally directed to compositions and methods for removing hydrogen sulfide, with improved hydrate resistance and cold stability, in an industrial process fluid or system. The hydrogen sulfide scavenger composition disclosed herein may include an aldehyde or aldehyde donor compound and a multifunctional hydrate inhibitor. Also, the hydrogen sulfide scavenger composition may include a solvent. The molar ratio of the aldehyde or aldehyde donor to the multi-functional quaternary ammonium compound in the composition is from about 0.05:1 to about 100:1.

Description

MULTIFUNCTIONAL HYDROGEN SULFIDE SCAVENGERRELATED APPLICATIONS

[0001] The present application is based on and claims priority to U.S. Provisional Patent application Serial No. 63 / 655,350, filed on June 03, 2024, which is incorporated herein by reference.BACKGROUND

[0002] The presence of hydrogen sulfide (H2S) is an ever-present problem within oilfield industry. H2S is very corrosive and highly hazardous / toxic to oilfield personnel and leads to the souring of the produced oil, which increases corrosion and higher pipeline failure. To mitigate / eliminate the effect of H2S, chemical additive(s), called H2S scavenger(s). are often applied in the oil field. In some cases, H2S mitigation is performed in offshore subsea and ultra-deepwater environments at low temperatures and high pressure.

[0003] Currently, formaldehy de-releasing chemicals are widely used as H2S scavengers in oil industry’ while zinc carboxylate is also used to scavenge H2S from crude oil. Antifreeze and anti-hydrate additives can be added to the H2S scavenger for cold stability and hydrate resistance in subsea and ultra-deepwater environment (e.g., umbilical applications). For instance, Hexahydro-1, 3, 5-tris(hydroxyethyl)-s-triazine (MEA-triazine) is the most widely used water-soluble fast H2S scavenger for quickly removing majority of H2S from gas, produced water and sometimes from crude oil. However, MEA-triazine is disadvantageous in terms of scale formation and corrosion to refinery. Thus, oil industry shows an increasing interest in triazine-free H2S scavenger. In addition, MEA-triazine is offered in the form of aqueous solution. Since water forms hydrate with methane, a hydrate inhibitor such as methanol needs to be added into MEA-triazine for umbilical applications.

[0004] Likewise, 3,3'-Methylene bis[5-methyl oxazolidine] (MBO) is also a fast H2S scavenger though not as fast as MEA-triazine. MBO is both water and oil-soluble, thus can be used in both produced water and crude oil. However, MBO has the similar disadvantages as MEA-triazine, namely scale formation and refinery corrosion. Unlike MEA-triazine, MBO is offered in the form of pure product. MBO is expected to be stable at umbilical temperature of 4°C due to the low freezing point of -30 °C. However, MBO's ability’ to form hydrate with methane is yet to be determined.

[0005] Also, (ethylenedioxy)dimethanol (EDDM) is a water-soluble H2S scavenger. Though EDDM does not cause refinery corrosion. EDDM is a slow scavenger whichrequires higher dose level and longer time to achieve low residual H2S level. This limits EDDM's use to e.g., downhole application, which allows longer contact time. In addition, EDDM is incompatible with methanol at 4 °C as the combination of EDDM and methanol results in precipitation.

[0006] Dimethyloldimethyl hydantoin (DMDMH) is another water-soluble slow H2S scavenger. Like EDDM, DMDMH does not cause refinery corrosion but requires higher dose level and longer time to achieve low residual H2S level. This limits DMDMH's use to e.g. downhole application, which allows longer contact time. Like EDDM, DMDMH is incompatible with methanol at 4 °C, as the combination of DMDMH and methanol results in precipitation.

[0007] Zinc 2-ethylhexanoate is an oil-soluble fast H2S scavenger. Zinc 2- ethylhexanoate is perhaps the most expensive H2S scavenger. Since zinc 2-ethylhexanoate is only oil-soluble and very expensive, zinc 2-ethylhexanoate's use is limited to polish crude oil to remove the last bit of H2S. Zinc 2-ethylhexanoate also causes scale formation which needs to be removed from the pipeline or tank as well as severe phase separation problems due to surface-active properties. Therefore, zinc 2-ethylhexanoate is not suitable for umbilical applications.

[0008] As such, a need exists for methods and compositions for H2S mitigation in umbilical conditions that are cold stable and hydrate resistant.SUMMARY

[0009] The present disclosure is generally directed to compositions and methods for removing hydrogen sulfide, with improved hydrate resistance and cold stability, in an industrial process fluid or system. The hydrogen sulfide scavenger composition disclosed herein may include an aldehyde or aldehyde donor compound and a multifunctional hydrate inhibitor. Also, the hydrogen sulfide scavenger composition may include a solvent. The molar ratio of the aldehyde or aldehyde donor to the multi-functional quaternary ammonium compound in the composition is from about 0.05: 1 to about 100: 1.

[0010] In one aspect, the hydrogen sulfide scavenger composition may include dimethyloldimethyl hydantoin (DMDMH); and didecyldimethylammonium chloride (DDAC), wherein the molar ratio of DMDMH to DDAC is from about 0. 1 : 1 to about 10: 1.

[0011] In another aspect, the present disclosure is directed to a method of removing hydrogen sulfide, and its corrosion products, in an industrial process fluid or system. The method may include adding to the fluid or system an effective amount of a compositiondisclosed herein. The composition may be stable at a temperature of from about -30 °C to about 10 °C in every 24 hours.

[0012] These and other features and aspects, embodiments and advantages of the present invention will become better understood with reference to the following description and appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figure, in which:

[0014] Figure 1 depicts hydrate resistance of a H2S scavenger.

[0015] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.DETAILED DESCRIPTION

[0016] Reference will now be made in detail to example embodiments of the disclosure. It is to be understood by one of ordinary skill in the art that the present disclosure is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

[0017] The present disclosure is generally directed to compositions and methods for removing hydrogen sulfide, with improved hydrate resistance and cold stability, in an industrial process fluid or system. The hydrogen sulfide scavenger composition disclosed herein may include an aldehyde or aldehyde donor compound and a multifunctional hydrate inhibitor. Also, the hydrogen sulfide scavenger composition may include a solvent. The molar ratio of the aldehyde or aldehyde donor to the multi-functional quaternary' ammonium compound in the composition is from about 0.05: 1 to about 100: 1.

[0018] Advantageously, the hydrogen sulfide scavenger composition disclosed herein may be a hydrate resistant cold stable antimicrobial hydrogen sulfide scavenger composition. The hydrogen sulfide scavenger composition may be stable (e.g., no precipitation) in umbilical conditions, such as at a temperature of from about -30 °C to about 10 °C in every 24 hours, such as from about -20 °C to about 5 °C in every 24 hours, such as from about -5 °C to about 2 °C in every 24 hours, or any range therebetween. As utilized herein, “umbilical conditions” refers to removal of hydrogen sulfide in a low temperature and high pressure environment of an umbilical system, such as those found in oil and gas operations. In one example embodiment, the composition may be stable at about 1 °C in every 24 hours.

[0019] The hydrogen sulfide scavenger composition disclosed herein may be hydrate resistant. As utilized herein "hydrate resistant'’ refers to preventing and / or inhibiting the formation of hydrates in gas. oil. water, or the like. In one example embodiment, the hydrogen sulfide scavenger composition disclosed herein may be hydrate resistant and cold stable at about less than 5 °C after about 24 hour exposure to from about 500 psi to about 5000 psi of gas, such as from about 1000 psi to about 4000 psi of gas, or any range therebetween. In one example embodiment, the hydrogen sulfide scavenger composition disclosed herein may be hydrate resistant and cold stable at about 4.4 °C after about 24 hour exposure to about 3000 psi of gas.

[0020] In one example embodiment, the composition disclosed herein may include an aldehyde or an aldehyde donor compound that is able to release, or to break down into, one or more molecules of an aldehyde. Advantageously, the aldehyde or aldehyde donor compound in the present composition is low temperature stable, water soluble, and may be effectively used as hydrogen sulfide scavengers. The aldehyde or aldehyde donor compound may include, but are not limited to, Ci-io aldehydes, formaldehyde, glutaraldehyde, (meth)acrolein or glyoxal, triazines such as hexahydro-1.3.5- tris(hydroxyethyl)-s-triazine (MEA-triazine), monoethanolamine triazine and monomethylamine triazine, and hydantoins, or mixtures thereof.

[0021] The aldehyde or aldehyde donor, for instance, may be a hydantoin. Hydantoins may include, but are not limited to hydroxyalkylhydantoins, bis(hydroxyalkyl)hydantoins, and dialkylhydantoins, where the alkyl group is generally a Ci-Ce alkyl group. For instance, the hydantoin may be selected from a group consisting of 1 -hydroxymethyl-5, 5- dimethyl-hydantoin (MDMH), 3-hydroxymethyl-5,5-dimethylhydantoin, dimethyloldimethyl hydantoin (DMDMH), 5,5-dimethylhydantoin, or mixtures thereof. In one example embodiment, the hydantoin may be dimethyloldimethyl hydantoin (DMDMH).

[0022] In one example embodiment, the aldehyde or aldehyde donor may be selected from a group consisting of dimethyloldimethyl hydantoin (DMDMH), hexahydro-1, 3,5- tris(hydroxyethyl)-s-triazine (MEA-triazine), (Ethylenedioxy )dimethanol (EDDM), and a combination thereof.

[0023] The aldehyde or aldehyde donor compound disclosed herein may be present in the hydrogen sulfide scavenger composition in an amount of from about 5% by weight to about 90% by weight, such as from about 15 wt.% by weight to about 80% by weight, such as from about 25% by weight to about 65% by weight, or any range therebetween.

[0024] In one example embodiment, the composition disclosed herein may include an aldehyde or aldehyde donor compound in combination with a multifunctional hydrate inhibitor. For instance, the molar ratio of the aldehyde or aldehyde donor to the multifunctional quaternary ammonium compound in the composition may be from about 0.05: 1 to about 100:1, such about from about 0.1:1 to about 50: 1, such as from about 0.5: 1 to about 40:1, such as from about 1: 1 to about 25: 1, such as from about 5: 1 to about 20:1, or any range therebetween. In one example embodiment, the molar ratio of the aldehyde or aldehyde donor to the multi-functional quaternary ammonium compound in the composition may be about 4:1.

[0025] In general, the multifunctional hydrate inhibitor may stabilize the composition disclosed herein in umbilical (e.g., cold) conditions and enable hydrate resistance. Additionally, the multifunctional hydrate inhibitor may enhance antimicrobial efficacy of the composition disclosed herein. The hydrate inhibitor may include a quaternary ammonium compound.

[0026] Quaternary ammonium compounds, also known as "quats", typically include at least one quaternary ammonium cation with an appropriate anion. Quats will generally have the general formula (1).

[0027] The groups Ri, R2, R3 and R4 can vary within wide limits and examples of quaternary ammonium compounds that have anti -microbial properties will be well known to the person of ordinary skill in the art. Typically, two of Ri, R2, R3 and R4 are lower alky l, meaning having 1 to 4 carbon atoms, such as methyl, ethyl, propyl or butyl groups. In addition, two of Ri, R2, Rs and R4 are longer chain alkyl groups of 6 to 24 carbon atoms, or a benzyl group. A' is a monovalent anion or one equivalent of a polyvalent anion of an inorganic or organic acid. Suitable anions for A’ are in principle all inorganic or organic anions, in particular halides, for example chloride or bromide, carbonates, bicarbonates, carboxylates, sulfonates, phosphates or a mixture thereof. Carboxylates may be derived from lower carboxylic acids or from fatty acids.

[0028] Alkyl, hereinafter, is taken to mean in each case unbranched or branched alkyl groups of the specified number of carbons, but preferably unbranched alkyl groups, andparticularly preferably those having an even number of carbon atoms. In particular, this is also taken to mean the homologue mixtures derived from natural raw materials, for example "‘cocoalkylT

[0029] In one example embodiment, the quaternary ammonium compound may have the following R groups: Ri is benzy l or Ce-18 alky l, R2 is Ci-is alkyl or — [(CH2)2 — O]nRs where n=l-20, R3 and R4 independently of one another are C1-4 alkyl, R5 is hydrogen or unsubstituted or substituted phenyl, and A is a monovalent anion or one equivalent of a polyvalent anion of an inorganic or organic acid.

[0030] Substituted phenyl is taken to mean, in particular, phenyl groups substituted with one or more Ci-18 alky l groups and / or halogen atoms.

[0031] Suitable quaternary ammonium compounds include, but are not limited to, alkyldimethylbenzyl ammonium chlorides, dialkylmethylbenzyl ammonium chlorides, dialkyldimethyl ammonium chlorides, alkyl dimethyl ethylbenzyl quaternary ammonium chlorides, benzethonium chloride and any combination of any of the foregoing.

[0032] In one example embodiment, the quaternary ammonium compound may include a dialkyl ammonium compound, such as a dimethyl dialkyl ammonium compound. In one example embodiment, the dimethyl dialkyl ammonium compound may have between about 8 and about 12 carbon atoms, such as from about 8 to about 10 carbon atoms in each of the alky l groups.

[0033] Examples of dimethyl dialkyl ammonium compounds include dimethyl dioctyl ammonium compounds such as dimethyl dioctyl ammonium chloride, dimethyl didecyl ammonium compounds such as dimethyl didecyl ammonium chloride and the like. Mixtures of dimethyl dialkyl ammonium compounds may also be used, and other anions, such as those described above, may also be used. Commercially available dimethyl dialkyl ammonium compounds include, for example, compositions marketed and sold under the BARDAC®, BARDAP®, BARQUAT®, or CARBOQU AT® trade names by Lonza Inc.

[0034] Such commercially available examples of dimethyl dialkyl ammonium compounds include dioctyldimethylammonium chloride (available as Bardac® LF and LF- 80 from Lonza, Inc.), octyldecyldimethylammonium chloride (available as a mixture of octyldecyldimethylammonium chloride, dioctyldimethylammonium chloride, and didecyldimethyl ammonium chloride as Bardac® 2050 and 2080 from Lonza, Inc.), didecyldimethy lammonium chloride (DDAC; available as Bardac® 2250 and 2280 from Lonza, Inc.), decylisononyldimethylammonium chloride (available as Bardac® 21 fromLonza, Inc.), diisodecyldimethylammonium chloride (available as BTC 99 from Stepan Co. of Northfield, Ill.), and any combination of any of the foregoing.

[0035] In an alternative example embodiment, the quaternary ammonium compound may include a benzyl ammonium compound, such as an alkyl dimethyl benzyl ammonium compound. In general, the alkyl group may contain from about 10 to about 18 carbon atoms, such as from about 12 to about 16 carbon atoms.

[0036] Examples of alkyl dimethyl benzyl ammonium compounds useable as the first biocide include C12 alkyl dimethyl benzyl ammonium chloride, C14 alkyl dimethyl benzyl ammonium chloride, and Ci6 alkyl dimethyl benzyl ammonium chloride. In addition, a mixture of these alkyl dimethy l benzyl ammonium compounds can be used. Commercially available alkyl dimethyl benzyl ammonium compounds include, for example, compositions marketed and sold under the BARQUAT® trade name by Arxada LLC. These commercially available alkyl dimethyl benzyl ammonium compounds are blends of C12, C14, and Ci6 alkyl dimethyl benzyl ammonium chlorides. Generally, it is preferable that the alky l dimethyl benzyl ammonium compound, when a blend, contains higher concentrations of C12 alkyl and C14 alkyl components than Ci6 alkyl components. It is noted that other anions, including those mentioned above may also be used.

[0037] Non-limiting examples of alkyldimethylbenzyl ammonium chlorides include alky l (C14 50%; C12 40%, Ci6 10%) dimethylbenzyl ammonium chloride (available as Barquat® MB-50 and MB-80 from Lonza Inc.), alkyl (C14 60%; Ci6 30%; C12 5%. Cis 5%) dimethylbenzyl ammonium chloride (available as Barquat® 4280Z from Lonza, Inc.), (C12- Cis alkyl) dimethylbenzyl ammonium chloride, and any7combination of any of the foregoing.

[0038] In still another example embodiment, the quaternary ammonium compound may include a quaternary ammonium carbonate. A quaternary ammonium carbonate can be represented by the following formula:

[0039] wherein R1 is a C1-C20 alkyl or aryl-substituted alkyl group and R2 is a C8-C20 alkyd group, and preferably wherein R1 is the same as R2 and R1 is a C8-C12 alkyl group,as well as compositions further including the corresponding quaternary7ammonium bicarbonate:?

[0040] wherein R1 is the same or a different C1-C20 alkyl or aryl-substituted alkyl group as above and R2 is the same or a different C8-C20 alkyl group as above, but preferably wherein R1 is the same as R2 and R1 is a C8-C12 alkyl group.

[0041] In one example embodiment, the quaternary ammonium compound may include a di C8-C 12 alkyl ammonium carbonate / bicarbonate. For instance, in one example embodiment, the quaternary ammonium compound may be didecyl dimethyl ammonium carbonate and didecyl dimethyl ammonium bicarbonate.

[0042] In other example embodiments, however, the carbonate / bicarbonate salts of quaternary ammonium cations may be selected from dioctyldimethylammonium carbonate, decyloctyldimethylammonium carbonate, benzalkonium carbonate, benzethonium carbonate, stearalkonium carbonate, cetrimonium carbonate, behentrimonium carbonate, dioctyldimethylammonium bicarbonate, decyloctyldimethylammonium bicarbonate, benzalkonium bicarbonate, benzethonium bicarbonate, stearalkonium bicarbonate, cetrimonium bicarbonate, behentrimonium bicarbonate, and mixtures of one or more such carbonate salts.

[0043] In one example embodiment, the hydrate inhibitor includes didecyldimethylammonium chloride (DDAC).

[0044] It should be understood that the quaternary ammonium compound may include more than one specific quaternary ammonium species and may include a combination of any of the above-described quaternary7ammonium compounds.

[0045] When provided as a concentrate or in the composition, the quaternary ammonium compound(s) may be present in the hydrogen sulfide scavenger composition disclosed herein in an amount of from about 5% by weight to about 60% by weight, such as from about 15% to about 50%, such as from about 25% to about 40%, or any range therebetween.

[0046] In one example embodiment, the hydrocarbon sulfide scavenger composition may include a solvent. For instance, the solvent may aid with the delivery' of the composition and / or provide the desired viscosity, stability, etc. In one example embodiment, the solvent may be water. In another example embodiment, the solvent may be an organic solvent. In another example embodiment, the solvent may be a combination of water and an organic solvent.

[0047] Suitable organic solvents should preferably not negatively impact the stability’ of the multifunctional hydrate inhibitor. Suitable solvents are, but are not limited to, alcohols, naphtha, benzene derivatives, ketones or esters, or mixtures of two or more of the aforementioned. Preferably the organic solvents may include at least one alcohol.

[0048] In one example embodiment, the solvent is selected from a group including naphtha or an aromatic petroleum distillate, or mixtures thereof. Preferably the solvent may include naphtha or benzene derivatives. Examples include, but are not limited to, naphtha, xylene, toluene or mixtures thereof.

[0049] The solvent combined with the multifunctional hydrate inhibitor may also include a mixture of any of the solvents described above. In one example embodiment, the solvent may include water. In one example embodiment, however, the composition is substantially free of water, e.g., such that the composition contains water in an amount less than about 5% by weight, such as in an amount less than about 2% by weight, such as in an amount less than about 1% by weight. In one example embodiment, for instance, the composition does not contain water and is water-free.

[0050] The organic solvent may include, but is not limited to, polar aprotic solvents, aromatic solvents, alcohols, glycols and derivatives such as glycol ethers, water-soluble esters, ketones, and the like. For instance, these solvents may include, but are not limited to, methanol, ethanol, 1 -propanol, isopropanol, butanol including n-butanol, isobutanol, and tert-butanol, pentanol, hexanol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polyethylene glycolpolyethylene glycol block copolymers, 2 -methoxy ethanol, diethylene glycol monomethyl ether, ethylene glycol monobutyl ether, butyl diglycol ether, water / oil-soluble C2-C10 esters, and water / oil-soluble C2-C10 ketones, cyclohexanone, diisobutylketone, N,- methylpyrrolidinone, N,N-dimethylformamide, pentane, hexane, cyclohexane, methylcyclohexane, heptane, decane, dodecane, and the like. The polar aprotic solvents may also include N,N-dimethyl formamide, dimethylsulfoxide, dimethylacetamide, 1-methyl-2-pyrrolidone, tetramethylene sulfone, acetone, formamide, acetonitrile, and the like. The aromatic solvents may include aromatic naphta, xylene, toluene, and the like.

[0051] In one example embodiment, the solvent may include water, propylene glycol, dipropylene glycol, methanol, or a mixture thereof. In another example embodiment, the solvent may be methanol.

[0052] However, it should be understood that the organic solvent is not limited to those mentioned above and that any organic solvent may be employed. In addition, a combination of organic solvents and water may be employed in the composition.

[0053] When provided as a concentrate or in the composition, the solvent may be present in the composition in an amount of from about 1 wt.% or more, such as about 5 wt.% or more, such as about 10 wt.% or more, such as about 25 wt.% or more, such as about 50 wt.% or more to about 95 wt.% or less, such as about 75 wt.% or less, such as about 50 wt.% or less, such as about 30 wt.% or less. When employed with an aqueous acidic solution, the solvent may be present in an amount of about 10 wt.% or more, such as about 20 wt.% or more, such as about 40 wt.% or more, such as about 60 wt.% or more to about 80 wt.% or less, such as about 60 wt.% or less, such as about 40 wt.% or less, such as about 20 wt.% or less.

[0054] If desired, the hydrogen sulfide scavenger composition may include a corrosion inhibitor. In one example embodiment, the corrosion inhibitor composition may be a base. In one example embodiment, the base may be a weak base. In one example embodiment, the base may be an organic amine. The organic amine may include one or more 1,2- or 1,3- alkanolamines encompassed by Formula I:R'NH (CHR2)n CHR3OH (Formula 1) wherein n=l or 2 and R1, R2, and R3are hydrogens or lower alkyl groups having a total number of carbons less than or equal to 4. Most preferred are 1,2-alkanolamines and 1,3- alkanol amines wherein:

[0055] In one example embodiment, the organic amine may be an alkylamine, a monoalkanolamine, a dialkanolamine, a trialkanolamine, or a combination thereof. For instance, the organic amine may be monoethanolamine, monopropanolamine, monoisopropanolamine, diethanolamine, dipropanolamine, triethanolamine, tripropanolamine, and the like, and mixtures thereof. The alkylamine may also include morpholines, anilines, ammonias, methylamine, dimethylamine, ethylamine, glycine, methylamine, trimethylamine, hydrazine, and the like, and mixtures thereof.

[0056] However, it should be understood that the base is not limited to those mentioned above and that any base may be employed. In addition, a combination of bases may be employed in the composition.

[0057] In one example embodiment, the hydrogen sulfide scavenger composition may include a hydrocarbon. As used herein, “hydrocarbon” refers to an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons may be aromatic hydrocarbons (arenes), alkanes, alkenes, cycloalkanes and alkyne-based compounds. Hydrocarbons may be saturated hydrocarbons (alkanes) composed entirely of single bonds and are saturated with hydrogen. The general formula for saturated hydrocarbons is CnH2n+2 (assuming noncyclic structures). Hydrocarbons may be unsaturated hydrocarbons having one or more double or triple bonds between carbon atoms such as alkenes and alkynes as defined above. Hydrocarbons may be cycloalkanes, which are hydrocarbons containing one or more carbon rings to which hydrogen atoms are attached. Hydrocarbons may be aromatic hydrocarbons, also known as arenes, are hydrocarbons that have at least one aromatic ring. Hydrocarbons may be a liquid hydrocarbon. The liquid hydrocarbon may be any type of liquid hydrocarbon including, but not limited to, crude oil, heavy oil, processed residual oil, bituminous oil, coker oils, coker gas oils, fluid catalytic cracker feeds, gas oil, naphtha, fluid catalytic cracking slurry, diesel fuel, fuel oil et fuel, gasoline, and kerosene.

[0058] The composition may further include one or more oil field additives selected from the group including scale inhibitors, emulsifiers, water clarifiers, dispersants, emulsion breakers, gas hydrate inhibitors, biocides, pH modifiers, surfactants, synergistic compounds, asphaltene inhibitors, paraffin inhibitors, antioxidants, pour point depressants, viscosity modifiers, flow back aids, friction reducers, or crosslinking agents. Unless otherwise specified, these additives typically are less than 5%, such as less than 2%, such as less than 1% by weight and generally greater than about 0.01% by weight. Such additives can be introduced into the well, wellbore or pipeline before, during or after the introduction of the foaming agent composition, or can be a component of said composition.

[0059] Suitable scale inhibitors include, but are not limited to, phosphates, phosphate esters, phosphoric acids, phosphonates, phosphonic acids, polyacrylamides, salts of acrylamido-methyl propane sulfonate / acrylic acid copolymer (AMPS / AA), phosphinated maleic copolymer (PHOS / MA), and salts of a polymaleic acid / acrylic acid / acrylamido- methyl propane sulfonate terpolymer (PMA / AMPS).

[0060] Suitable emulsifiers include, but are not limited to, salts of carboxylic acids, products of acylation reactions between carboxylic acids or carboxylic anhydrides and amines, and alkyl, acyl and amide derivatives of saccharides (alkyl-saccharide emulsifiers).

[0061] Suitable water clarifiers include, but are not limited to, inorganic metal salts such as aluminum chloride, and aluminum chlorohydrate, or organic polymers such as acrylic acid based polymers, acrylamide based polymers, polymerized amines, alkanolamines, thiocarbamates, and cationic polymers such as diallyldimethylammonium chloride (DADMAC).

[0062] Suitable dispersants include, but are not limited to, aliphatic phosphonic acids with 2-50 carbons, such as hydroxyethyl diphosphonic acid, and aminoalkyl phosphonic acids, e.g. polyaminomethylene phosphonates with 2-10 N atoms e.g. each bearing at least one methylene phosphonic acid group; examples of the latter are ethylenediamine tetra(methylene phosphonate), diethylenetriamine penta(methylene phosphonate) and the triamine- and tetramine-polymethylene phosphonates with 2-4 methylene groups between each N atom, at least 2 of the numbers of methylene groups in each phosphonate being different. Other suitable dispersion agents include lignin or derivatives of lignin such as lignosulfonate and naphthalene sulfonic acid and derivatives.

[0063] Suitable emulsion breakers include, but are not limited to, dodecylbenzylsulfonic acid (DDBSA), the sodium salt of xylene sulfonic acid (NAXSA), epoxylated and propoxylated compounds, anionic cationic and nonionic surfactants, and resins, such as phenolic and epoxide resins.

[0064] Suitable gas hydrate inhibitors include, but are not limited to, thermodynamic inhibitors (THI), kinetic inhibitors (KHI), and anti-agglomerates (AA). Suitable thermodynamic inhibitors include, but are not limited to, NaCl salt, KC1 salt, CaCi2 salt, MgCh salt, NaB2 salt, formate brines (e.g. potassium formate), polyols (such as glucose, sucrose, fructose, maltose, lactose, gluconate, monoethylene glycol, diethylene glycol, triethylene glycol, mono-propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, monobutylene glycol, dibutylene glycol, tributylene glycol, glycerol, diglycerol, triglycerol, and sugar alcohols (e.g. sorbitol, mannitol), methanol, propanol,ethanol, glycol ethers (such as diethyleneglycol monomethyl ether, ethylene glycol monobutyl ether), and alkyl or cyclic esters of alcohols (such as ethyl lactate, butyl lactate, methylethyl benzoate). Suitable kinetic inhibitors and anti-agglomerates include, but are not limited to, polymers and copolymers, polysaccharides (such as hydroxy-ethylcellulose (HEC), carboxymethylcellulose (CMC), starch, starch derivatives, and xanthan), lactams (such as polyvinylcaprolactam, polyvinyl lactam), pyrrolidones (such as polyvinyl pyrrolidone of various molecular weights), surfactants (such as fatty acid salts, ethoxylated alcohols, propoxylated alcohols, sorbitan esters, ethoxylated sorbitan esters, polyglycerol esters of fatty acids, alkyl glucosides, alkyl polyglucosides, alkyl sulfates, alkyl sulfonates, alkyl ester sulfonates, alkyl aromatic sulfonates, alkyl betaine, alkyl amido betaines), hydrocarbon based dispersants (such as lignosulfonates, iminodisuccinates, polyaspartates), amino acids, and proteins.

[0065] Any biocide suitable in oilfield operations may be used. A biocide may be included in a composition in an amount of about 0. 1 ppm to about 1000 ppm on a weight basis. Suitable biocides include, but are not limited to, oxidizing and non-oxidizing biocides. Suitable non-oxidizing biocides include, for example other quaternary ammonium compounds (e.g., quaternary amine compounds and cocodiamine), halogenated compounds (e.g., bronopol and 2-2-dibromo-3-nitrilopropionamide (DBNPA)), sulfur compounds (e.g., carbamates, and metronidazole), and quaternary phosphonium salts (e.g., tetrakis(hydroxymethyl)phosphonium sulfate (THPS)). Suitable oxidizing biocides include, for example, sodium hypochlorite, trichloroisocyanuric acids, dichloroisocyanuric acid, calcium hypochlorite, lithium hypochlorite, chlorinated hydantoins, stabilized sodium hypobromite, activated sodium bromide, brominated hydantoins, chlorine dioxide, ozone, and peroxides.

[0066] Suitable pH modifiers include, but are not limited to, alkali hydroxides, alkali carbonates, alkali bicarbonates, alkaline earth metal hydroxides, alkaline earth metal carbonates, alkaline earth metal bicarbonates and mixtures or combinations thereof. Exemplary pH modifiers include NaOH, KOH, Ca(OH)2, CaO, Na2COi, KHCO3, K2CO3, NaHCCh. MgO, and Mg(OH)2.

[0067] In one embodiment, the pH of the composition disclosed herein may be from about 4 to about 9, such as from about 5 to about 8, or any range therebetween.

[0068] Any antioxidant suitable in oilfield operations may be used. Exemplary antioxidants include but are not limited to sulfites, thiocyanates and thiosulfates. Anantioxidant may be included in a composition in an amount of about 1 ppm to about 1000 ppm on a weight basis.

[0069] The hydrogen sulfide scavenger composition may be prepared or mixed using any technique known in the art. For instance, as one example, the components may be mixed simultaneously. As another example, aldehyde or aldehyde donor compound may be mixed first with the multifunctional hydrate inhibitor. Thereafter, additional components such as a solvent, a surfactant, an alkynol, etc. may be added to the mixture. Further, the hydrogen sulfide scavenger composition may be premixed, prepackaged, and transported to a site, such as a well site, for use.

[0070] The hydrogen sulfide scavenger composition may have utility during acidizing treatments for hydrocarbon wells, such as those in the oil and gas industries, as well as nonhydrocarbon wells, such as water wells and geothermal wells. In these applications, the hydrogen sulfide scavenge composition may provide corrosion mitigation to equipment including casings, tubings, and other well components such as wellhead fittings, connections, meters, storage tanks, flow lines, etc. Further, the hydrogen sulfide scavenge composition may also be used in other industrial settings to mitigate corrosion of tanks, process lines, pumps, heaters, boilers, cooling towers, and other industrial equipment.

[0071] While acidizing treatments and acid stimulation are mentioned, it should be noted that the hydrogen sulfide scavenge composition may have multiple uses. For instance, the hydrogen sulfide scavenge composition may have applications relating to the production, transportation, storage, and separation of oil and gas. Additionally, the hydrogen sulfide scavenge composition may be employed for other processes such as pickling a tubular, cleaning a wellbore, acid tunneling, drilling mud removal, and scale treatment.

[0072] The preceding description is exemplary in nature and is not intended to limit the scope, applicability or configuration of the disclosure in any way. Various changes to the described embodiments may be made in the function and arrangement of the elements described herein without departing from the scope of the disclosure.

[0073] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention is related.

[0074] As used in this application and in the claims, the singular forms “a”, “an”, and “the” include the plural forms unless the context clearly dictates otherwise. Additionally, the term “includes” means “comprises”. The methods and compositions of the presentdisclosure, including components thereof, can comprise, consist of, or consist essentially of the essential elements and limitations of the embodiments described herein, as well as any additional or optional ingredients, components or limitations described herein or otherwise useful in hydrogen sulfide scavenger compositions.

[0075] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, percentages, and so forth, as used in the specification or claims are to be understood as being modified by the term “about”. Accordingly, unless otherwise indicated, implicitly or explicitly, the numerical parameters set forth are approximations that may depend on the desired properties sought and / or limits of detection under standard test conditions / methods. When directly and explicitly distinguishing embodiments from discussed prior art, the embodiment numbers are not approximates unless the word “about” is recited.

[0076] As used herein, “optional” or “optionally” means that the subsequently described material, event or circumstance may or may not be present or occur, and that the description includes instances where the material, event or circumstance is present or occurs and instances in which it does not. As used herein, “w / w%” and “wt%” mean by weight as relative to another component or a percentage of the total weight in the composition.

[0077] The term “about” is intended to mean approximately, in the region of, roughly, or around. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. Unless otherwise indicated, it should be understood that the numerical parameters set forth in the following specification and attached claims are approximations. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, numerical parameters should be read in light of the number of reported significant digits and the application of ordinary rounding techniques.

[0078] The term “substantially free of’ when used to describe the amount of substance in a material is not to be limited to entirely or completely free of and may correspond to a lack of any appreciable or detectable amount of the recited substance in the material. Thus, e.g., a material is “substantially free of’ a substance when the amount of the substance in the material is less than the precision of an industry-accepted instrument or test for measuring the amount of the substance in the material. In certain example embodiments, a material may be “substantially free of’ a substance when the amount of the substance in the material is less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than5%, less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, or less than 0.1% by weight of the material.

[0079] The phrase “effective amount” means an amount of a compound that promotes, improves, stimulates, or encourages a response to the particular condition or disorder or the particular symptom of the condition or disorder.

[0080] As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

[0081] Here and throughout the specification and claims, range limitations are combined and interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0082] This written description uses examples to disclose the present disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0083] Furthermore, certain aspects of the present disclosure may be better understood according to the following examples, which are intended to be non-limiting and exemplary in nature. Moreover, it will be understood that the compositions described in the examples may be substantially free of any substance not expressly described.EXAMPLESExample 1Static Cold Stress Test of H2S Scavenger Formulations

[0084] In sequence, dimethyloldimethyl hydantoin (DMDMH, 55% active), (ethylenedioxy )dimethanol (EDDM, 95% active), diethyloldimethyl hydantoin (DEDMH, 90% active), didecyldimethylammonium chloride (DDAC, 50% active), deionized water and methanol were charged into a 20 mL scintillation vial (See Table 1 for detailedcompositions). The mixtures were shaken manually at ambient temperature for homogeneous solution.Table 1. Formulations of H2S Scavenger* 50% DDAC / 37.5% Methanol / 12.5% Water

[0085] The formulated H2S scavenger samples were stored in a fridge at 4 °C for 7 days. The samples were visually inspected for any precipitates formed at 4 °C at an interval of 24 hours. To pass the 4 °C static cold stress test, no precipitates should be observed after 7 days. As shown in Table 2, the presence of DEDMH or DDAC in the formulation improve the cold stability of DMDMH and EDDM scavenger to pass the 4 °C static cold stress test while the presence of >50 wt.% methanol gives worse cold stability than DMDMH and EDDM alone.Table 2. 4 °C Static Cold Stress Test of H2S Scavenger FormulationsExample 2Semi-Centrifuge Cold Stress Test oflhS Scavenger Formulations

[0086] In sequence, DMDMH (55%), DDAC (50%) or methanol were charged into a 50 mL centrifuge tube (See Table 3 for detailed compositions). The mixtures were shaken manually at ambient temperature to generate a homogeneous solution.Table 3. Formulations of H2S Scavenger

[0087] The formulated H2S scavenger samples were stored in a fridge at 4 °C for 7 days. At an interval of 24 hour, the samples were centrifuged at 2000 rpm and 4 °C for 5 minutes and then visually inspected for any precipitates at the bottom of the centrifuge tube. To pass the 4 °C semi-centrifuge cold stress test, no precipitates should be observed after 7 days. As shown in Table 4, the formulations of DMDMH scavenger with < 20 wt.% methanol or < 50 wt.% DDAC pass the 4°C semi-centrifuge cold stress test.Table 4. 4 °C Semi-Centrifuge Cold Stress Test of H2S Scavenger FormulationsExample 3Centrifuge Cold Stress Test of IhS Scavenger Formulations

[0088] In sequence, DMDMH (55%), DDAC (50%) or methanol were charged into a 300 mL beaker (See Table 5 for detailed compositions). The mixtures were magnetically mixed at ambient temperature, and the resulting homogenous solutions were filtered through 20-25 mm filter paper.Table 5. Formulations of H2S Scavenger

[0089] The formulated hydrogen sulfide scavenger samples were constantly centrifuged at 3000 rpm and 1 °C for 7 days. Afterwards, the samples were visually inspected for any particles / precipitates at the bottom of the centrifuge tube. To pass the 1 °C centrifuge cold stress test, no significant particles / precipitates should be observed after constant centrifugation for 7 days. As shown in Table 6, the formulation of DMDMH scavenger with DDAC passes the 1 °C centrifuge cold stress test while the formulation of DMDMH with methanol does not.Table 6. 1 °C Centrifuge Cold Stress Test of H2S Scavenger FormulationsExample 4Hydrate Resistance ofHiS Scavenger Formulation

[0090] In sequence, DMDMH (55%) and DDAC (50%) were charged into a 300 mL beaker (See Table 7 for detailed compositions). The mixture was magnetically mixed at ambient temperature and the resulting homogenous solution was filtered through 20-25 mm filter paper.Table 7. Formulation of H2S Scavenger

[0091] The sample was subject to 2,000 psi with Green Canyon synthetic gas at 40 °F for 24 hours. The approximate subcooling under these conditions is 27.8 °F. This procedure tests against check-valve failure scenarios during an umbilical application where neat chemicals may be exposed to natural gas under high pressure / low temperature conditions, which may result in a hydrate plug in the umbilical if the product contains water as part of the formulation. The product was pressurized in a constant volume rocking cell to 2,100 psi using Green Canyon synthetic gas. The rocking cell was submerged in a temperature-controlled tank and cooled down to 40 °F with a chiller and programmed to rock the test cell for 26 hours.Table 8. Hydrate Resistance of H2S Scavenger Formulation

[0092] These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.

Claims

What Is Claimed;1. A hydrogen sulfide scavenger composition, the composition comprising: an aldehyde or aldehyde donor; and a multifunctional hydrate inhibitor, wherein the molar ratio of the aldehy de or aldehyde donor to the multifunctional quaternary ammonium compound is from about 0.05: 1 to about 100: 1.

2. The composition of claim 1, wherein the aldehyde or aldehyde donor comprises dimethyloldimethyl hydantoin (DMDMH), hexahydro-1, 3, 5-tris(hydroxyethyl)-s-triazine (MEA-triazine), (Ethylenedioxy)dimethanol (EDDM), or a combination thereof.

3. The composition of claim 1, wherein the aldehyde or aldehyde donor comprises dimethyloldimethyl hydantoin (DMDMH).

4. The composition of claim 1 , wherein the multifunctional hydrate inhibitor comprises a quaternary' ammonium compound.

5. The composition of claim 4, wherein the quaternary ammonium compound is selected from a group consisting of alk ldi methylbenzyl ammonium chlorides, dialkylmethylbenzyl ammonium chlorides, dialkyldimethyl ammonium chlorides, alkyl dimethyl ethylbenzyl quaternary ammonium chlorides, benzethonium chloride or a combination thereof.

6. The composition of claim 5, wherein the dialkyl ammonium compound comprises dioctyldimethylammonium chloride, octyldecyldimethylammonium chloride, didecyldimethylammonium chloride (DDAC), decylisononyldimethylammonium chloride, diisodecyldimethylammonium chloride, or a combination thereof.

7. The composition of claim 5, wherein the quaternary' ammonium compound comprises didecyldimethylammonium chloride (DDAC).

8. The composition of claim 1, wherein the molar ratio of the aldehyde or aldehyde donor to the multifunctional quaternary ammonium compound is from about 1 : 1 to about 25:1.

9. The composition of claim 1, wherein the molar ratio of the aldehyde or aldehyde donor to the multifunctional quaternary ammonium compound is about 4: 1.

10. The composition of claim 1, further comprising a solvent.

11. The composition of claim 10, wherein the solvent comprises water, methanol, or a combination thereof.

12. The composition of claim 10, wherein the solvent comprises water.

13. The composition of claim 10, wherein the solvent comprises methanol.

14. The composition of claim 1, wherein the composition is stable at a temperature of from about -30 °C to about 10 °C in every724 hours.

15. The composition of claim 14, wherein the composition is stable at a temperature of from about -5 °C to about 2 °C in every724 hours.

16. The composition of claim 1, wherein the composition is hydrate resistant at from about 500 psi of gas to about 5000 psi.

17. The composition of claim 16, wherein the composition is hydrate resistant at from about 1000 psi of gas to about 4000 psi.

18. A composition hydrogen sulfide scavenger composition, the composition comprising: dimethyloldimethyl hydantoin (DMDMH); and didecyldimethylammonium chloride (DDAC), wherein the molar ratio of DMDMH to DDAC is from about 0.1: 1 to about 10:1.

19. A method of removing hydrogen sulfide, and its corrosion products, in an industrial process fluid or system, the method comprises: adding to the fluid or system an effective amount of a composition comprising: an aldehyde or aldehyde donor; and a multifunctional hydrate inhibitor.wherein the molar ratio of the aldehyde or aldehyde donor to the multifunctional quaternary ammonium compound is from about 0.05: 1 to about 100: 1, wherein the composition is stable at a temperature of from about -30 °C to about 10 °C in ever}724 hours.

20. The method of claim 19, wherein the industrial process system is selected from a group consisting of an oil and gas production system, a produced water storage tank, an oil storage tank, an oil or gas transmission pipeline, ballast water tank, or oil transportation tank.

21. The method of claim 19, wherein the industrial process system is an oil storage tank or transport system.

22. The method of claim 19, wherein the industrial process fluid is a fracturing fluid or a drilling mud.

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