WO2015042028A1

WO2015042028A1 - High temperature stable cross-linked polymers

Info

Publication number: WO2015042028A1
Application number: PCT/US2014/055815
Authority: WO
Inventors: Krishnan Tamareselvy; Cory G. Miller; Hyungsoo KIM
Original assignee: The Lubrizol Corporation
Priority date: 2013-09-18
Filing date: 2014-09-16
Publication date: 2015-03-26
Also published as: AR097704A1

Abstract

This disclosed technology relates to a viscosifying agent for use in a composition and/or process for drilling and cementing, including use of the agent as a gelling agent for hydraulic fracturing and/or enhanced oil recovery. The viscosifying agent is a cross-linked polymer made up of units derived from a unique mixture of monomers. The polymer has good effectiveness as a viscosifying agent while also having good high temperature stability.

Description

HIGH TEMPERATURE STABLE CROSS-LINKED POLYMERS

[0001] This disclosed technology relates to a viscosifying agent for use in a composition and/or process for drilling, cementing, hydraulic fracturing, and/or enhanced oil recovery. The viscosifying agent is a cross-linked polymer made up of units derived from a unique mixture of monomers. The polymer has good effectiveness as a viscosifying agent while also having good high temperature stability.

BACKGROUND

[0002] Water based drilling fluids often contain viscosifying agents such as starches, guar gum, guschleroglucans, polyacrylates, and a wide variety of synthetic and natural polymers to establish and control the theological properties of the drilling fluid. During the course of drilling a subterranean well, water based drilling fluids are exposed to temperatures that can be in excess of 300°F (149°C). Exposure to such temperatures can have a detrimental effect on viscosifying agents, resulting in a loss in viscosity of the fluid at high temperatures. A breakdown of the rheology, i.e., loss in viscosity, can result in the drilling fluid being unable to suspend the solids dispersed within it such as the weighting or bridging agent or even the drill cuttings which can lead to severe problems such as settlement, loss in fluid density and possibly a blowout of the well.

[0003] One of skill in the art will appreciate that at least a portion of the loss in viscosity is the result of the drilling fluid becoming less viscous as the temperature of the drilling fluid increases. However, this thermally induced loss in viscosity does not fully explain the observed drop in viscosity at higher temperatures over time. It has been reported that one likely cause for the loss in viscosity is the degradation of the polymers, starches, and other compounds used as viscosifying agents in the drilling fluid. A wide variety of compositions have been used to try and delay the degradation of viscosifying agents and to extend the temperature limit at which a particular drilling fluid formulation can be used. Two materials commonly added to help stabilize the high temperature rheology of a drilling fluid are magnesium oxide and monoethanolamine. Both compounds serve as to buffer the pH of the drilling fluid and thus maintain the alkaline conditions under which the process of hydrolysis or degradation of the polymers is retarded.

[0004] Despite the widespread use of these compounds, there exists an unmet need for viscosifying agents that do not require the addition of such stabilizers and/or that provide improved performance over the viscosifying agents available today. Thus, there remains a continuing need for new thermally stable viscosifying agents for use in aqueous wellbore fluids and/or fracturing fluids.

[0005] The disclosed technology seeks to provide a thermally stable viscosifying agent for use in aqueous wellbore fluids.

SUMMARY

[0006] The disclosed technology provides a polymer that includes units derived from: (A) a first monomer composition including an ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomer, where the monomer includes at least one alkyl group containing 5 to 30 carbon atoms, or salts thereof; (B) a second monomer composition including one or more ethylenically unsaturated polymerizable monomers, or salts thereof; and (C) a third composition comprising one more crosslinking agents; wherein the second monomer of (B) is different from the first monomer of (A).

[0007] The disclosed technology provides for embodiments where (B), the second monomer composition, comprises at least one of: (i) one or more ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomers where the monomers of free of any alkyl groups containing more than 4 carbon atoms or salts thereof; (ii) one or more carboxylic acid monomers or partial esters, or salts thereof; (iii) one or more amide monomers; (iv) one or more alkoxylated hydrophobically modified associative monomers; (v) one or more phosphonic acid monomers or partial esters, or salts thereof; (vi) one or more vinyl monomers; or (vii) any combination thereof.

[0008] The disclosed technology provides for embodiments where (B) comprises one or more ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomers where the monomers are free of any alkyl groups containing more than 4 carbon atoms. [0009] The disclosed technology provides for embodiments where (B) comprises a compound having the structure:

where R⁴ is an alkyl group containing 1 to 4 carbon atoms; R⁵ is hydrogen or an alkyl group containing from 1 to 4 carbon atoms; and R⁶ is an alkyl group containing 1 to 4 carbon atoms; and R⁷ is hydrogen or a methyl group; or a metal, ammonium, or alkylamine salt thereof.

[0010] The disclosed technology provides for embodiments where (B) comprises 2-acrylamido-2-methypropane-l -sulfonic acid, a mono or multivalent metal of one or more thereof, an ammonium salt or one or more thereof, an alkylamine salt of one or more thereof or a combination thereof.

[0011] The disclosed technology provides for embodiments where (B) comprises one or more ethylenically unsaturated polymerizable carboxylic acid monomers, or salts and/or esters or partial esters thereof.

[0012] The disclosed technology provides for embodiments where (B) comprises acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid or salts and/or esters or partial esters thereof.

[0013] The disclosed technology provides for embodiments where (B) comprises one or more acrylamide monomers.

[0014] The disclosed technology provides for embodiments where (B) comprises one or more ethylenically unsaturated amido functional monomers selected from acrylamide, methyl acrylamide, methyl methacrylamide, N-alkylmethacrylamide, Ν,Ν-dialkylmethacrylamide, N-alkylacrylamide, and N,N-dialkylacrylamide.

[0015] The disclosed technology provides for embodiments where (C) includes ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1 ,3-butylene glycol di(meth)acrylate, 1 ,4-butylene glycol di(meth)acrylate, 1 ,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1 ,9-nonanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; dipentaerythritol hexa(meth)acrylate, 1 ,4-cyclohexanediol dimethyacrylate, a polyallyl ether of sucrose having from 2 to 8 allyl groups per molecule, a pentaerythritol diallyl ether, a pentaerythritol triallyl ether, a pentaerythritol tetraallyl ether, a trimethylolpropane diallyl ether, a trimethylolpropane triallyl ether, Ν,Ν'-methylenebisacrylamide, diacrylamide, 1, 1 - bisacrylamido-2-methylpropane sulfonic acid and its salts, or any combination thereof.

[0016] The disclosed technology provides for embodiments where (C) includes a borate or one or more polyvalent metal ions selected from the group consisting of zirconium, chromium, titanium, aluminum, and mixtures thereof.

[0017] Examples of suitable crosslinking agents that can be utilized include, but are not limited to the following: boron compounds such as boric acid, disodium octaborate tetrahydrate, sodium diborate, pentaborate, or combinations thereof; compound that can supply chromium (III) ions such as chromium acetate, chromium lactate, chromium citrate or combinations thereof; compounds that can supply zirconium (IV) ions such as zirconium diethanolamine complex, zirconium triethanolamine complex, zirconium lactate, zirconium ethylene glycolate, zirconium acetylacetonate, tetrakis(triethanolaminato)zirconium, zirconium ammonium lactate, zirconium diethanol lactate, zirconium triethanolamine lactate, zirconium diisopropylamine lactate, zirconium sodium lactate salts, zirconium glycerol complex, zirconium sorbitol complex, zirconium hydroxyalkylated ethylenediamine complexes, or combinations thereof; compounds that can supply titanium (IV) ions such as titanium ammonium lactate, titanium triethanolamine, and titanium acetylacetonate; aluminum compounds such as aluminum lactate and aluminum citrate.

[0018] The disclosed technology provides for embodiments where the polymer further comprises units derived from: (D) a fourth monomer composition comprising one or more monomers that include an alkyl group containing 1 to 18 carbon atoms comprising a simple ester, a vinyl ester, an mono-allyl ether, or salts thereof, or any combination thereof.

[0019] The disclosed technology provides for embodiments where (A) comprises a compound having the structure:

where R 1 is an alkyl group containing from 5 to 30 carbon atoms; R 2 is hydrogen or an alkyl group containing from 1 to 30 carbon atoms; and R is an alkyl group containing 1 to 4 carbon atoms; and R⁷ is hydrogen or a methyl group; or a metal, ammonium, or alkylamine salt thereof.

[0020] The disclosed technology provides for embodiments where (A) comprises 2- acrylamido-2-dodecane sulfonic acid, 2-acrylamido-2-hexadecane sulfonic acid, 2- acrylamido-2-octadecane sulfonic acid, 2-acrylamido-2-decane sulfonic acid, 2- acrylamido-2-octane sulfonic acid, 2-acrylamido-2-diisobutane sulfonic acid, 2- acrylamido-2-heptadecane sulfonic acid, 2-acrylamido-2-pentadecane sulfonic acid, 2- acrylamido-2-decane-2-octane sulfonic acid, 2-acrylamido-2-hexane sulfonic acid, 2- acrylamido-2-heptane sulfonic acid, 2-methacrylamido-2-dodecane sulfonic acid, 2- methacrylamido-2-hexadecane sulfonic acid, 2-methacrylamido-2-octadecane sulfonic acid, 2-methacrylamido -2-decane sulfonic acid, 2-methacrylamido-2-octane sulfonic acid, 2-metacrylamido-2-hexane sulfonic acid, 2-metacrylamido-2-heptane sulfonic acid, 2-methacrylamido-2-diisobutane sulfonic acid, 2-methacrylamido-2-heptadecane sulfonic acid, 2-methacrylamido-2-pentadecane sulfonic acid, 2-methacrylamido-2- decane-2-octane sulfonic acid, an alkali metal of one or more thereof, an ammonium salt or one or more thereof, an alkylamine salt of one or more thereof, or a combination thereof.

[0021] The disclosed technology provides for embodiments where the polymer is made up of: 0.1 to 50, or 0.1 to 30, or even 0.1 to 10 percent by weight of monomer units derived from (A); and 1 to 99.89 or 30 to 99.89, or 50 to 99.89, or even 70 to 99.89 percent by weight of monomer units derived from (B); and 0.01 to 50 or even 0.01 to 20 percent by weight units derived from (C).

[0022] The disclosed technology provides for embodiments where the polymer is made up of: 0.1 to 50, or 0.1 to 30, or even 0.1 to 10 percent of monomer units derived from (A); 25 to 99.88 or from 45 to 99.88, or from 65 to 99.88 percent by weight units derived from (B); and 0.01 to 50 or even 0.01 to 20 percent by weight units derived from (C), and 0.01 to 49 or even 1 to 49 or even 0.01 to 5 percent by weight units derived from (D).

[0023] The disclosed technology provides for embodiments where the polymer is free of units derived from an alkylene glycol monomer.

[0024] The disclosed technology provides for embodiments where the polymer units derived from the compounds of (A) have the following structures:

R⁷

R¹- -R²

R³

SO*H

wherein: R 1 is an alkyl group containing from 5 to 24 carbon atoms; R 2 is hydrogen or an alkyl group containing from 1 to 10 carbon atoms; R is an alkyl group containing 1 to 4 carbon atoms; R⁷ is hydrogen or a hydrocarbyl group. The disclosed technology provides for embodiments where the polymer units derived from the compounds of (A) is present as a sulfonic acid as shown above or an alkali metal or ammonium salt thereof.

[0025] The disclosed technology provides for a process of making a polymer comprising the steps of: (I) reacting: (A) a first monomer composition comprising an ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomer, where the monomer includes at least one alkyl group containing 5 to 30 carbon atoms, or salts thereof; (B) a second monomer composition comprising one or more ethylenically unsaturated polymerizable monomers, or salts thereof; and (C) a third composition comprising one more crosslinking agents; wherein the second monomer composition (B) is different from the first monomer composition (A). The disclosed technology provides for embodiments where the process is a solution polymerization, a precipitation polymerization, a gel polymerization, or an inverse emulsion polymerization.

[0026] The disclosed technology provides for embodiments where step (I) of the process further comprises reacting: (D) a fourth monomer composition comprising one or more monomers that include an alkyl group containing 1 to 18 carbon atoms comprising a simple ester, a vinyl ester, an mono-allyl ether, or any combination thereof; with (A), (B), and (C).

[0027] The disclosed technology provides for the use of the described polymer as a viscosifying agent and/or fluid loss control agent in a cement composition and/or in a cementing process.

[0028] The disclosed technology provides for the use of the described polymer as a friction reducer, viscosifying agent, fluid loss control agent, and/or a gelling agent in a hydraulic fracturing process.

[0029] The disclosed technology provides for methods that include the use of the described polymer as a viscosifying agent and/or fluid loss control agent in a drilling composition and/or in a drilling process.

[0030] The disclosed technology provides for methods that include the use of the described polymer as a viscosifying agent or a gelling agent in an enhanced oil recovery process.

DETAILED DESCRIPTION

[0031] Various preferred features and embodiments will be described below by way of non-limiting illustration.

[0032] The disclosed technology provides a polymer including units derived from: (A) a first monomer composition comprising an ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomer, where the monomer includes at least one alkyl group containing 5 to 30 carbon atoms, or salts thereof; (B) a second monomer composition comprising one or more ethylenically unsaturated polymerizable monomers, or salts thereof; and (C) a third composition comprising one more crosslinking agents; wherein the second monomer composition (B) is different from the first monomer composition (A).

[0033] In some embodiments, (A) and (B) differ in that the monomers of (B) do not contain a pendant alkyl group that includes more than 4 carbon atoms, while the monomers of (A) must include a pendant alkyl group containing from 5 to 30 carbon atoms.

[0034] In some embodiments, (A) and (B) differ in that the monomers of (A) have a higher number average molecular weight than the monomers of (B).

[0035] In some embodiments, (A) and (B) differ in that the monomers of (A) have the specific structure defined below for it, and the monomers of (B) have the specific structure defined below for it. In other embodiments, the monomer of (B) are ethylenically unsaturated amidoalkanesulfonic acids, partial esters thereof, or full esters thereof.

[0036] In some embodiments, more than 50%, on a molar basis, of the monomers that become part of the described polymers are ionic. In other words, in some embodiments the described polymer is made up of units where more than 50% of the units are ionic, such that the polymer may be described as ionic.

[0037] The monomers of (A) may include ethylenically unsaturated, water- soluble sulfonic acid monomers that have been hydrophobically modified and include polymerizable sulfonic acids such as unsaturated hydrocarbylamidoalkanesulfonic acids that have been hydrophobically modified, for example, acrylamido- or methacrylamidosulfonic acids hydrophobically modified by the addition of a long hydrocarbyl or alkyl substituent group. In one embodiment, the ethylenically unsaturated water-soluble polymerizable sulfonic acid can be an unsaturated-hydrocarbylamido-alkanesulfonic acid.

[0038] In some embodiments, the monomers of (A) may include a compound having the structure:

where R 1 is an alkyl group containing from 5 to 30 carbon atoms; R 2 is hydrogen or an alkyl group containing from 1 to 30 carbon atoms; and R is an alkyl group containing 1 to 4 carbon atoms; and R⁷ is hydrogen or a methyl group; or a metal, ammonium, or alkylamine salt thereof. In some embodiments, R¹ is an alkyl group containing from 5 to 30 carbon atoms, or from 5 to 24, or from 6 to 24, or from 8 to 22, or from 6 to 18, or from 10 to 16 carbon atoms, or even 10, 14 or 16 carbon atoms. In some embodiments, R is hydrogen or an alkyl group containing from 1 to 30 carbon atoms, or even from 1 to

10, 1 to 8 or even 1 or 8 carbon atoms. In some embodiments, R is an alkyl group containing 1 to 4 carbon atoms, or even just 1 carbon atom. In some embodiments, R⁷ is hydrogen or a methyl group.

[0039] Suitable examples for the monomers of (A) include 2-acrylamido-2- dodecane sulfonic acid, 2-acrylamido-2-hexadecane sulfonic acid, 2-acrylamido-2- octadecane sulfonic acid, 2-acrylamido-2-decane sulfonic acid, 2-acrylamido-2- octane sulfonic acid, 2-acrylamido-2-hexane sulfonic acid, 2-acrylamido-2-heptane sulfonic acid, 2-acrylamido-2-diisobutane sulfonic acid, 2-acrylamido-2- heptadecane sulfonic acid, 2-acrylamido-2-pentadecane sulfonic acid, 2- acrylamido-2-decane-2-octane sulfonic acid, 2-methacrylamido-2-dodecane sulfonic acid, 2-methacrylamido-2-hexadecane sulfonic acid, 2-methacrylamido-2- octadecane sulfonic acid, 2-methacrylamido -2-decane sulfonic acid, 2- methacrylamido-2-octane sulfonic acid, 2-metacrylamido-2-hexane sulfonic acid, 2- metacrylamido-2-heptane sulfonic acid, 2-methacrylamido-2-diisobutane sulfonic acid, 2-methacrylamido-2-heptadecane sulfonic acid, 2-methacrylamido-2- pentadecane sulfonic acid, 2-methacrylamido-2-decane -2 -octane sulfonic acid, an alkali metal of one or more thereof, an ammonium salt or one or more thereof, an alkylamine salt of one or more thereof, or a combination thereof. [0040] The monomers of (B) may include one or more various monomers that differ from the monomers of (A).

[0041] The monomers of (B) may include at least one of: (i) one or more ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomers where the monomers of free of any alkyl groups containing more than 4 carbon atoms or salts thereof; (ii) one or more carboxylic acid monomers or partial esters, or salts thereof; (iii) one or more amide monomers; (iv) one or more alkoxylated hydrophobically modified associative monomers; (v) one or more phosphonic acid monomers or partial esters, or salts thereof; (vi) one or more vinyl monomers; or (vii) any combination thereof.

[0042] In some embodiments, the monomers of (B) include: (i) one or more ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomers where the monomers of free of any alkyl groups containing more than 4 carbon atoms or salts thereof.

[0043] In such embodiments, the monomers of (B) may include ethylenically unsaturated, water-soluble sulfonic acid monomers and include polymerizable sulfonic acids such as unsaturated hydrocarbylamidoalkanesulfonic acids, for example, acrylamido- or methacrylamidosulfonic acids, where the monomers are free of any alkyl groups containing more than 4 carbon atoms.

[0044] In one embodiment, the monomers of (B) may include ethylenically unsaturated, water-soluble sulfonic acid monomers and include polymerizable sulfonic acids such as unsaturated hydrocarbylamidoalkanesulfonic acids, for example, acrylamido- or methacrylamidosulfonic acids. In one embodiment, the ethylenically unsaturated water-soluble polymerizable sulfonic acid can be an unsaturated-hydrocarbylamido-alkanesulfonic acid. The pendent group can also include phenyl groups, alkyl substituted phenyl groups and cycloaliphatic groups.

[0045] In one embodiment, the monomers of (B) may include a compound having the structure:

where R⁴ is an alkyl group containing 1 to 4 carbon atoms; R⁵ is hydrogen or an alkyl group containing from 1 to 4 carbon atoms; and R⁶ is an alkyl group containing 1 to 4 carbon atoms; and R⁷ is hydrogen or a methyl group; or a metal, ammonium, or alkylamine salt thereof. In some embodiments, R⁴ is an alkyl group containing less than 4 carbon atoms, 1 to 4 carbon atoms, or even just 1 carbon atom. In some embodiments, R⁵ is hydrogen or an alkyl group containing less than 4 carbon atoms, from 1 to 4 carbon atoms or even just 1 carbon atom. In some embodiments, R⁵ is hydrogen or a methyl group. In some embodiments, R⁶ is an alkyl group containing 1 to 4 carbon atoms or even just 1 carbon atom. In some embodiments, R⁷ is hydrogen or a methyl group. Any of these embodiments may also include a metal, ammonium, or alkylamine salt thereof.

[0046] In embodiments where the monomers of (B) include a metal salt of compound described above, suitable metals include either alkali or alkaline metals. In some embodiments, the metal is calcium.

[0047] In embodiments where the monomers of (B) include an alkylamine salt of compound described above, suitable alkylamines include lipophilic amines and/or lipophilic amine salts. The amine ion, that is, the amine in its cationic form, can be represented by:

r8_r9r10_r11_n+ where R⁸, R⁹, R¹⁰ and R¹¹ are independently hydrogen or hydrocarbyl groups, provided that at least one of R⁸, R⁹, R¹⁰ and R¹¹ is a hydrocarbyl group of sufficient length suitable to impart lipophilic properties. The term "amine salt" or "amine ions" includes ions or salts, where up to three of the R groups are hydrocarbyl groups, and quaternary amine ions or salts, where each of the R groups is a hydrocarbyl group. In order to provide suitable lipophilic character, the total carbon atoms in the amine ion should be at least 6, and in one embodiment at least 10, or at least 14. In certain embodiments, the total number of carbon atoms in an amine cation does not exceed 36 carbon atoms; thus the total number of carbon atoms may be, e. g., 6 to 36. Examples of suitable amines include N, N- dimethyl -n- dodecylamine, 2-ethylhexylamine, tri-n-butylamine, triisobutylamine, triisooctylamine, tripropylamine, trihexylamine, trioctylamine, decylamine, dodecylamine, tridecylamine, tridodecylamine, hexadecylamine, octadecylamine, oleylamine, higher tert-alkyl primary amines such as Primene 81R™ and Primene JMT™ from Rohm and Haas, and aromatic amines such as pyridines, benzylamine, N-methylbenzylamine, 2-phenethylamine, aniline, and substituted anilines.

[0048] As used herein, the term "lipophilic" is given its conventional meaning that is, interacting favorably with or being soluble in non-polar or fatty solvents. A synonym for "lipophilic" is "hydrophobic," which may be contrasted with "hydrophilic." Hydrophobic materials exhibit little or no favorable interaction with water and are generally not appreciably soluble in water or similarly polar solvents. The hydrophobic or hydrophilic character of a material can also be understood to approximately correlate with results derived from the octanol/water partition test. The original form of this test, involving measurement of the equilibrium concentration of a dissolved substance in a two-phase system of n-octanol and water, as well as a chromatographic method, are described in ASTM E-1 147-92 and provides a value P, where P = C₀ctanoi/C_water. The hydrophilic or hydrophobic nature of an amine in question can be evaluated by comparing its P value with the P values of other amines, as those listed above, which are known to be appropriately lipophilic materials.

[0049] These alkylamines and the salts made of the same are described in greater detail in US patent application 2008/0221253.

[0050] In some embodiments, the monomers of (B) include 2-acrylamido-2- methypropane-1 -sulfonic acid, a mono or multivalent metal of one or more thereof, an ammonium salt or one or more thereof, an alkylamine salt of one or more thereof or a combination thereof.

[0051] In some embodiments, the monomers of (B) include: (ii) one or more carboxylic acid monomers or partial esters, or salts thereof. In such embodiments, the monomers of (B) may comprise one or more ethylenically unsaturated polymerizable carboxylic acid monomers, or salts and/or esters or partial esters thereof. Suitable examples include what are often referred to as carboxylic monomers or aery late monomers.

[0052] Additional examples of suitable carboxylic acid monomers, or partial esters, full esters, or salts thereof, include: Sipomer COPS^®-I, commercially available from Rhodia, which is a 40% aqueous solution of sodium allyl ether sulfonate and sodium l-allyloxy-2-hydroxypropyl sulfonate, having a molecular weight of about 218; vinyl benzene sulfonic acids, vinyl benzene sulfonates, alkyl vinyl benzene sulfonic acids, alkyl vinyl benzene sulfonates for example SPINOMAR^® NaSS, commercially available from Tosoh, which is a sodium p- styrene sulfonate having a molecular weight of about 206; 2- sulfoethylmetahcrylate; alkylvinyl sulfonic acids, alkyl vinyl sulfonates for example sodium vinyl sulfonate (SVS); sodium allylsulfonate (SAS); sodium methally sulfonate (SMAS); acrylic acid-(3-sulfonpropyl)ester and potassium salts thereof (SPA); methacrylic acid-(3-sulfonpropyl)ester and potassium salts thereof (SPM), or any combination thereof.

[0053] In some embodiments, the monomers of (B) are essentially free of any acrylate monomers. In some embodiments, the monomers of (B) are free of any acrylate monomers. In some embodiments, the polymers described herein are essentially free of any acrylate monomers. In some embodiments, the polymers described herein are free of any acrylate monomers.

[0054] In other embodiments, the monomers of (B) include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid or salts and/or esters thereof. The esters thereof include full and partial esters thereof.

[0055] In some embodiments, the monomers of (B) include one or more compounds having the structural formula:

(R¹²)(R¹³)C=C(R¹⁴)(R¹⁵)

wherein: R¹² is H or CH₃; R¹³ is H or COOH; R¹⁴ is H or COOH; and R¹⁵ is H,

COOH or CH₂COOH; provided that when R¹² is H and R¹³ is COOH, R¹⁴ and R¹⁵ are different and are either H or COOH; when R¹² and R¹³ are both H, R¹⁴ is COOH and R¹⁵ is CH₂COOH; and when R¹² is CH₃, R¹³ is COOH and R¹⁴ and R¹⁵ are different and are either H or COOH. Suitable examples include maleic acid, itaconic acid, fumaric acid, citraconic acid and mesaconic acid.

[0056] In some embodiments, the monomers of (B) include: (iii) one or more amide monomers. In such embodiments, the monomers of (B) may include one or more acrylamide monomers, which may also be described as ethylenically unsaturated ami do functional monomers.

[0057] Suitable examples include acrylamide, methyl acrylamide, methyl methacrylamide, N-alkylmethacrylamide, Ν,Ν'-dialkylmethacrylamide, N- alkylacrylamide, Ν,Ν'-dialkylacrylamide, and any combination thereof.

[0058] In some embodiments the monomers of (B) include Ν,Ν'- dimethylacrylamide, t-butylacrylamide, t-octylacrylamide, or a combination thereof.

[0059] In some embodiments, the monomers of (B) include: (iv) one or more alkoxylated hydrophobically modified associative monomers. In other embodiments the polymer is free of units derived from alkoxylated hydrophobically modified associative monomers.

[0060] In some embodiments, the monomers of (B) include: (v) one or more phosphonic acid monomers or partial esters, or salts thereof. In other embodiments the polymer is free of units derived from phosphonic acid monomers or partial esters, or salts thereof.

[0061] In some embodiments the monomers of (B) include: (vi) one or more vinyl monomers. In other embodiments the polymer is free of units derived from more vinyl monomers.

[0062] The polymer described herein includes units derived from (C) a third composition comprising one or more crosslinking agents.

[0063] Suitable crosslinking agents include polyfunctional acrylates, polyalkenyl polyethers, or a combination thereof.

[0064] Polyfunctional acrylates have at least two polymerizable ethylenically unsaturated double bonds. The term "polyfunctional acrylate" refers to acrylate esters of organic polyols wherein the organic polyol is esterified by reacting it with (meth)acrylic acid. The polyfunctional acrylate can contain 2 to 6 polymerizable ethylenically unsaturated double bonds. Suitable polyols for the esterification reaction can contain 2 to 12 carbon atoms and have at least two hydroxyl groups. The polyol can be linear and branched or cyclic. Exemplary polyols suitable for esterification include, but are not limited to, alkylene glycols containing 2 to 5 carbon atoms , polyalkylene glycol dimers and trimers, trimethylolethane and dimers thereof, trimethylolpropane and dimers thereof, triethylolpropane and dimers thereof, tetramethylolmethane (pentaerythritol), dipentaerythritol, and 1 ,4- cyclohexanediol.

[0065] Useful polyfunctional acrylates include, but are not limited to, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1 ,3-butylene glycol di(meth)acrylate, 1 ,4-butylene glycol di(meth)acrylate, 1 ,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1 ,9-nonanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; dipentaerythritol hexa(meth)acrylate, 1 ,4-cyclohexanediol dimethyacrylate, and mixtures thereof.

[0066] The polyalkenyl polyether has at least two polymerizable ethylenically unsaturated double bonds. The term "polyalkenyl polyether" refers to alkenyl ethers of organic polyols wherein the organic polyol is etherified by reacting it with alkenyl halide, such as allyl chloride or allyl bromide. The polyalkenyl polyether (e.g., polyallyl polyether) can contain 2 to 8 polymerizable ethylenically unsaturated double bonds. Suitable polyols for the etherification reaction can contain 2 to 12 carbon atoms and have at least two hydroxyl groups. The polyol can be linear and branched or cyclic (e.g., monosaccharides and polysaccharides containing 1 to 4 saccharide units). Exemplary polyols suitable for etherification include, but are not limited to, glucose, galactose, fructose, sorbose, rhamnose, sucrose, arabinose, maltose, lactose, raffinose, pentaerythritol, dipentaerythritol, trimethylolethane and dimers thereof, trimethylolpropane and dimers thereof, and triethylolpropane and dimers thereof. Additional polyols suitable for the etherification are disclosed in U.S. Patent No. 2, 798,053, the disclosure of which is hereby incorporated by reference. [0067] Useful polyalkenyl polyethers include, but are not limited to, polyallyl ethers of sucrose having from 2 to 8 allyl groups per molecule, pentaerythritol diallyl ether, pentaerythritol triallyl ether, and pentaerythritol tetraallyl ether; trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, and mixtures thereof.

[0068] In some embodiments, (C) includes ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1 ,3-butylene glycol di(meth)acrylate, 1 ,4- butylene glycol di(meth)acrylate, 1 ,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1 ,9-nonanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; dipentaerythritol hexa(meth)acrylate, 1 ,4-cyclohexanediol dimethyacrylate, a polyallyl ether of sucrose having from 2 to 8 allyl groups per molecule, a pentaerythritol diallyl ether, a pentaerythritol triallyl ether, a pentaerythritol tetraallyl ether, a trimethylolpropane diallyl ether, a trimethylolpropane triallyl ether, Ν,Ν'- methylenebisacrylamide, diacrylamide, 1 , 1 -bisacrylamido-2-methylpropane sulfonic acid and its salts, or any combination thereof.

[0069] The disclosed technology also provides for embodiments where (C) includes a borate or one or more polyvalent metal ions selected from the group consisting of zirconium, chromium, titanium, aluminum, and mixtures thereof..

[0070] Such crosslinking agents generally comprise a borate, a metal, transition metal, or metalloid, collectively referred to herein as "metal(s)." Examples include boron, aluminum, antimony, zirconium, magnesium, or titanium. Generally, the metal of a crosslinking agent interacts with at least two functional groups to form a crosslink to generate the polymer network. Under the appropriate conditions (e.g., pH and temperature), the crosslinks that form between polymer molecules may increase the viscosity of a viscosified treatment fluid.

[0071] Examples of suitable crosslinking agents that can be utilized include, but not are not limited to the following: boron compounds such as boric acid, disodium octaborate tetrahydrate, sodium diborate, pentaborate, or combinations thereof; compound that can supply chromium (III) ions such as chromium acetate, chromium lactate, chromium citrate or combinations thereof; compounds that can supply zirconium (IV) ions such as zirconium diethanolamine complex, zirconium triethanolamine complex, zirconium lactate, zirconium ethylene glycolate, zirconium acetylacetonate, tetrakis(triethanolaminato)zirconium, zirconium ammonium lactate, zirconium diethanol lactate, zirconium triethanolamine lactate, zirconium diisopropylamine lactate, zirconium sodium lactate salts, zirconium glycerol complex, zirconium sorbitol complex, zirconium hydroxyalkylated ethylenediamine complexes, or combinations thereof; compounds that can supply titanium (IV) ions such as titanium ammonium lactate, titanium triethanolamine, and titanium acetylacetonate; aluminum compounds such as aluminum lactate and aluminum citrate.

[0072] In some embodiments (C) includes only organic crosslinkers and is free of the borate and/or polyvalent metal ions described above. In such embodiments, the crosslinker may be added during the polymerization reaction. In these embodiments, the polymer may contain from 0.01 to 50 or 0.01 to 20, 0.01 to 10, 0.1 to 5, or 0.1 to 3, or even 0.5 to 1.0 percent by weight units derived from (C).

[0073] In other embodiments, (C) includes only borate and/or polyvalent metal ions crosslinkers and is free of the organic crosslinkers described above. In such embodiments the crosslinker may be added after the polymerization reaction. In these embodiments, the crosslinker may be added to the polymer such that the weight ratio of polymer to crosslinker used is from 1 :99 to 99: 1 or from 1 :50 to 50: 1 or from 1 : 10 to 10: 1 or from 1 :5 to 5 : 1 or evem from 1 : 1.5 to 1.5 : 1. In still other embodiments, the crosslinker may be added to the polymer such that the weight ratio of polymer to crosslinker used is from 1 : 1 to 1 :99 or from 1 : 1 to 1 : 10 or from 1 : 1 to 1 :5 or even from 1 : 1 to 1 : 1.5.

[0074] In some embodiments, the polymer further comprises units derived from: (D) a third monomer composition comprising one or more monomer that includes an alkyl group containing 1 to 18 carbon atoms comprising a simple ester, a vinyl ester, an mono-allyl ether, or salts thereof, or any combination thereof.

[0075] In some embodiments, the monomers of (D) can include acrylamides, methacrylamides, diacetone acrylamides, acrylic or methacrylic acids or their esters, vinyllactams such as vinyl pyrrolidone or vinyl caprolactam, and vinyl esters. In some embodiments, the monomers of (D) include acrylamide, dimethyl amino ethyl methacrylate quaternized with dimethyl sulfate or with an alkyl halide, methacryloyl oxyethyl trimethyl ammonium chloride; methacryloyl oxyethyl trimethyl ammonium methosulfate; or any combination thereof.

[0076] In some embodiments, the monomers of (D) may include: vinyl pyrrolidone/dialkylaminoalkyl acrylate or methacrylate, optionally quaternized; dimethyl amino ethyl methacrylate, vinyl caprolactam, and vinyl pyrrolidone; vinyl pyrrolidone and methacrylamidopropyl dimethyl amine; vinyl pyrrolidone and quaternized dimethyl amino propyl methacrylamide; and quaternary ammonium salts formed by the reaction of diethyl sulfate and a copolymer of vinyl pyrrolidone and dimethyl aminoethylmethacrylate.

[0077] In some embodiments, the monomers of (D) may include vinyl pyrrolidone and/or vinyl imidazole, optionally quaternized; vinyl pyrrolidone, acrylamide and vinyl imidazole, optionally quaternized; vinyl caprolactam, vinyl pyrrolidone and vinyl imidazole, optionally quaternized; vinyl pyrrolidone, vinyl imidazole, and diallyldimethyl ammonium chloride, optionally quaternized; or any combination thereof.

[0078] In still other embodiments, the monomers of (D) may include compounds selected form the group consisting of alkyvinyl sulfonic acids, alkyl vinyl sulfonates, vinyl benzene sulfonic acids, vinyl benzene sulfonates, alkyl vinyl benzene sulfonic acids, alkyl vinyl benzene sulfonates, and combinations of two or more thereof.

[0079] Suitable examples include but are not limited to compounds selected from the group consisting of N-vinyl acetamide, N-vinyl-N-methyl acetamide, N,N- dimethyl acetamide, N-vinyl-2-pyrrolidone, N-ethenyl-N-alkyl acetamide, and combinations of two or more thereof.

[0080] Suitable examples include but are not limited to compounds selected from the group consisting of ethylenically unsaturated N-substituted carboxylic acids selected from the group consisting of acrylamide, methyl acrylamide methylmethacry amide, N-alkylmethacrylamide, Ν,Ν-dialkylmethacrylamide, N- alkylacrylamide, Ν,Ν-dialkylacrylamide, and combinations of any two or more thereof. [0081] Suitable examples include but are not limited to compounds selected from the group consisting of acrylic acid, salts of acrylic acid, methacrylic acid, salts of methacrylic acid, itaconic acid, salts of itaconic acid, acrylonitrile, alkoxy esters of acrylic acid, alkoxy esters of methacrylic acid, vinyl sulfonate, vinyl sulfonic acid and combinations of any two or more thereof.

[0082] In some embodiments, the monomers of (D) include one or more vinyl esters selected from vinyl acetate, vinyl propionate, vinyl butanoate, vinyl valerate, vinyl hexanoate, vinyl octanoate, vinyl nonanoate, vinyl decanoate, vinyl neodecanoate, vinyl undecanoate, vinyl laurate, or any combination thereof.

[0083] In some embodiments, the monomers of (D) include one or more mono- allyl ethers selected from mono-allyl ethers of sucrose, mono-allyl ethers of pentaerythritol, or any combination thereof.

[0084] In other embodiments, the monomers of (D) are essentially free of, or even completely free of, vinyl esters. In other embodiments, the monomers of (D) are essentially free of, or even completely free of, mono-allyl ethers. In other embodiments, the monomers of (D) are essentially free of, or even completely free of, acrylamides, methacrylamides, diacetone acrylamides, acrylic or methacrylic acids or their esters. In other embodiments, the monomers of (D) are essentially free of, or even completely free of, vinyllactams such as vinyl pyrrolidone or vinyl caprolactam, and vinyl esters. In other embodiments, the monomers of (D) are essentially free of, or even completely free of, alkyvinyl sulfonic acids, alkyl vinyl sulfonates, vinyl benzene sulfonic acids, vinyl benzene sulfonates, alkyl vinyl benzene sulfonic acids, and alkyl vinyl benzene sulfonates.

[0085] In some embodiments, the polymer described herein is essentially free of, or even completely free of, units derived from an alkylene glycol monomer.

[0086] In some embodiments, the polymer described herein is made up of: 0.1 to 50, or 0.1 to 30, or even 0.1 to 10 percent by weight of monomer units derived from (A); and 1 to 99.89 or 30 to 99.89, or 50 to 99.89, or even 70 to 99.89 percent by weight of monomer units derived from (B); and 0.01 to 50 or 0.01 to 20, 0.01 to 10, 0.1 to 5, or 0.1 to 3, or even 0.5 to 1.0 percent by weight units derived from (C). Here we are describing the percent of the total units that make up the polymer which are derived from the monomers of (A) and the percent of the total units that make up the polymer which are derived from the monomers of (B) and the percent of the total units that make up the polymer which are derived from (C).

[0087] In some embodiments, the polymer described herein is made up of: 0.1 to 50, or 0.1 to 30, or even 0.1 to 10 percent of monomer units derived from (A); 25 to 99.88 or from 45 to 99.88, or from 65 to 99.88 percent by weight units derived from (B); 0.01 to 50 or 0.01 to 20, 0.01 to 10, 0.1 to 5, or 0.1 to 3, or even 0.5 to 1.0 percent by weight units derived from (C); and 0.01 to 49 or even 1 to 49 or even 0.01 to 5 percent by weight units derived from (D). Here we are describing the percent of the total units that make up the polymer which are derived from the monomers of (A) and the percent of the total units that make up the polymer which are derived from the monomers of (B) and the percent of the total units that make up the polymer which are derived from the monomers of (C) and the percent of the total units that make up the polymer which are derived from the monomers of (D).

[0088] In some embodiments, the polymer described herein includes units derived from the compounds of (A) that have the following structure:

R¹ -R²

R³

SO^H

wherein: R 1 is an alkyl group containing from 5 to 24 carbon atoms; R 2 is hydrogen or an alkyl group containing from 1 to 10 carbon atoms; R is an alkyl group containing 1 to 4 carbon atoms; R⁷ is hydrogen or a hydrocarbyl group; or an alkali metal or ammonium salt thereof. In some embodiments, R¹ is an alkyl group containing from 5 to 24 carbon atoms or from 6 to 24, or from 8 to 22, or from 6 to 18, or from 10 to 16, or even 10, 14 or 16 carbon atoms. In some embodiments, R is hydrogen or an alkyl group containing from 1 to 10 carbon atoms, or from 1 to 8, or even just 8 carbon atoms. In some embodiments, R is an alkyl group containing 1 to 4 carbon atoms, or even just 1 carbon atom. In some embodiments, R⁷ is hydrogen or a hydrocarbyl group, or even just hydrogen or a methyl group.

[0089] The disclosed technology includes process of making the described polymers. Such processes include the step of reacting: (A) a first monomer composition comprising an ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomer, where the monomer includes at least one alkyl group containing 5 to 30 carbon atoms, or salts thereof; and (B) a second monomer composition comprising one or more ethylenically unsaturated polymerizable monomers, or salts thereof; wherein the second monomer composition (B) is different from the first monomer composition (A).

[0090] Any of the monomers of (A) described above may be used in the process.

Likewise, any of the monomers of (B) described above may be used in the process.

[0091] The process may be carried out as a solution polymerization, a precipitation polymerization, a gel polymerization, or an inverse emulsion polymerization.

[0092] In some embodiments, the process is carried out as a solution polymerization. In some embodiments, the process is carried out as a precipitation polymerization. In some embodiments, the process is carried out as a gel polymerization. In some embodiments, the process is carried out as an inverse emulsion polymerization.

[0093] In some embodiments, the reaction step of the process further comprises reacting: (D) a fourth monomer composition comprising one or more monomers that include an alkyl group containing 1 to 18 carbon atoms comprising a simple ester, a vinyl ester, an mono-allyl ether, or any combination thereof; with (A) and (B).

[0094] Any of the monomers of (D) described above may be used in the process.

[0095] The disclosed technology includes the use of the polymer described herein as a viscosifying agent. The disclosed technology also includes methods of using the polymer described herein as a viscosifying agent. In some embodiments, the viscosifying agent disclosed here can have a number average molecule weight even above one million Dalton after crosslinking and such high molecular weight polymers can act as a fluid loss control agent, a shale inhibitor agent, a friction reducer, a gelling agent, or any combination thereof.

[0096] The viscosifying agent described herein may be used in drilling fluids. Generally, drilling fluids are characterized by the characteristics of the compound or mixture of compounds that make up the continuous phase of the drilling fluids. For example an aqueous-based drilling fluid is principally composed of an aqueous solution as the continuous phase. The aqueous based continuous phase may generally be any water based fluid phase that is compatible with the formulation of a drilling fluid and is compatible with the shale hydration inhibition agents disclosed herein. In one embodiment, the aqueous based continuous phase is selected from: fresh water, sea water, brine, mixtures of water and water soluble organic compounds and mixtures thereof. The amount of the aqueous based continuous phase should be sufficient to form a water based drilling fluid. This amount may range from nearly 100% of the drilling fluid to less than 30% of the drilling fluid by volume. In some embodiments, the aqueous based continuous phase is from about 95 to about 30% by volume water or even from about 90 to about 40%) by volume of the drilling fluid.

[0097] In addition to the aqueous continuous phase, the aqueous based drilling fluid typically includes polymeric viscosifying agent and a fluid loss control agent or simply a fluid loss agent. The drilling fluids of the disclosed technology include the viscosifying agent described herein, present in an amount sufficient to alter or maintain the rheological properties of the fluid.

[0098] The drilling fluids described herein may also include a weight material in order to increase the density of the fluid. The primary purpose for such weighting materials is to increase the density of the drilling fluid so as to prevent kick-backs and blow-outs. One of skill in the art should know and understand that the prevention of kick-backs and blow-outs is important to the safe day to day operations of a drilling rig. Thus the weight material is added to the drilling fluid in a functionally effective amount largely dependent on the nature of the formation being drilled. Weight materials suitable for use in the formulation of the drilling fluids of the claimed subject matter may be generally selected from any type of weighting materials be it in solid, particulate form, suspended in solution, dissolved in the aqueous phase as part of the preparation process or added afterward during drilling. It is preferred that the weight material be selected from the group including barite, hematite, iron oxide, calcium carbonate, alkali halides, alkaline earth halides, magnesium carbonate, zinc halides, zinc formates, zinc acetates, cesium halides, cesium formates, cesium acetates, as well as other well-known organic and inorganic salts, and mixtures and combinations of these compounds and similar such weight materials that may be utilized in the formulation of drilling fluids.

[0099] In addition to the components noted above, the described drilling fluids may also be formulated to include materials generically referred to as gelling materials, thinners, and fluid loss control agents, as well as other compounds and materials which are optionally added to water base drilling fluid formulations. Of these additional materials, each can be added to the formulation in a concentration as Theologically and functionally required by drilling conditions. Typical fluid loss control agents and gelling materials used in aqueous based drilling fluids are polyanionic carboxymethylcellulose (AC or CMC), chemically modified starches, bentonite, sepiolite, clay, attapulgite clay, anionic high-molecular weight polymers and biopolymers. Thinners such as lignosulfonates are also often added to water- base drilling fluids. Typically lignosulfonates, modified lignosulfonates, polyphosphates and tannins are added. In other embodiments, low molecular weight polyacrylates can also be added as thinners. Thinners are added to a drilling fluid to reduce flow resistance and control gelation tendencies. Other functions performed by thinners include reducing filtration and filter cake thickness, counteracting the effects of salts, minimizing the effects of water on the formations drilled, emulsifying oil in water, and stabilizing mud properties at elevated temperatures.

[0100] Other additives that could be present in the drilling fluids described herein include products such as shale inhibition agents, shale encapsulation agents, such as polyamides and glycols, lubricants, penetration rate enhancers, defoamers, corrosion inhibitors and loss circulation products. Such compounds should be known to one of ordinary skill in the art of formulating aqueous based drilling fluids.

[0101] The above section has described the application of the described viscosifying agent to a drilling fluid, which may include drilling muds, completion fluids, workover fluids and the like. However, one of skill in the art should immediately appreciate that the utilization of the thermal stability agents disclosed herein may extended to other types of viscosified wellbore fluids such as cementing fluids, fracturing fluids, packer fluids, annulus fluids, and the like which are utilized in the drilling and production of oil and gas from subterranean wells. Thus it is contemplated that the application of the thermal stability agents disclosed herein may be more extensive than is disclosed above and the use of the term "wellbore fluid" is intended to encompass that broader class of viscosified fluids including for example fracturing fluids.

[0102] The described technology may also be useful as thermally stable and salt tolerant gelling agent. The compositions described here may be used as associative hydrophobic thickeners, and the compositions can demonstrate good thermal stability and good salt tolerances, properties needed in hydraulic fracturing and other applications where one needs to transport a proppant. Various gelling agents have been used along with a crosslinking agent to thicken aqueous solutions in order to transport a proppant in hydraulic fracturing applications. However many gelling agents contain significant amounts of water insoluble material which can cause issues in fracturing jobs due to a loss of formation permeability as well as degradation at high temperature resulting in viscosity loss. Some materials have been used for water shut-off treatment, but they are often subject to hydrolysis at high temperature and high brine conditions and their crosslinking ability may become poorly controllable. The technology described herein provides a composition with good hydrophobic association properties where thickening is enhanced when the materials is crosslinked with multi-valent metals. These resulting polymers can be used as gelling agents that perform well under high temperature and salt conditions. Thus the compositions are useful for hydraulic fracturing applications and similar uses.

[0103] The amount of each chemical component described is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, that is, on an active chemical basis, unless otherwise indicated. However, unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by- products, derivatives, and other such materials which are normally understood to be present in the commercial grade.

[0104] As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include: (i) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form a ring); (ii) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy); (iii) hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. Heteroatoms include sulfur, oxygen, and nitrogen. In general, no more than two, or no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; alternatively, there may be no non- hydrocarbon substituents in the hydrocarbyl group. In some embodiments, the hydrocarbyl groups described herein are alkyl groups.

[0105] It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions (of, e.g., a detergent) can migrate to other acidic or anionic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not be susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components described above. [0106] The disclosed technology may be better understood with reference to the following examples.

EXAMPLES

Example 1 - Monomer preparations

[0107] 2 -acrylamidododecane-1 -sulfonic acid (C_HAMPS) - Acrylonitrile (4,414 g) and 1-dodecene (3,366 g) were charged to a 12 liter resin kettle flask equipped with a Teflon stirring blade, thermowell, and condenser. Oleum (sulfuric acid with 20% free SO3) (2,276 g) was added dropwise over 5 hours at 5°C. The ratio of acrylonitrile, 1 -dodecene, and oleum was 4.16: 1 : 1.16 by mole. The reaction was stirred overnight and C_HAMPS (1 ,020 g) was formed as a white precipitate. This solid was slowly settled, filtered, washed with acrylonitrile, and dried in vacuum.

[0108] 2 -aery lamidohexadecane-1 -sulfonic acid (C_HAMPS) - C_HAMPS (1 ,275 g) was prepared in the same manner as the above example with the exception that 1 - hexadecene was added instead of 1 -dodecene. The molar ratio of 1 -hexadecene compared to the other ingredients was the same as that of 1 -dodecene.

[0109] 2 -acrylamidooctadecane-l -sulfonic acid (C_HAMPS) - C_HAMPS (1, 194 g) was prepared in the same manner as the above two examples with the exception that 1 -octadecene was added instead of 1 -dodecene. The molar ratio of 1 - octadecene compared to the other ingredients was the same as that of 1-dodecene. Example 2 - Precipitation Copolymer preparations

[0110] Comparative copolymers as well as inventive polymers were prepared using a four neck flask fitted with a nitrogen inlet and thermocouple on one neck and a half moon stirrer on another, a condenser on another, and a stopper on another. A monomer mixture of 2-acrylamido-2-methylpropane-l -sulfonic acid (AMPS™2404) and the desired co-monomers including crosslinker, trimethylolpropane triacrylate (TMPTA) was added to the reactor. The total monomer amount is 60.5g. Tertiary butanol (350g) and ammonium hydroxide 30 wt% aqueous solution (15.4g) were added to the reactor. The mixture was placed under nitrogen at about 0.5 CFH and the slurry heated in a water bath set at about 60°C under stirring. The mixture began clearing then slowly became hazy then milky. After 30 min, dilauryl peroxide (0.75 g) was added. The reaction was held at about 60°C for about an hour and refluxed at about 75°C for about three hours. Dilauryl peroxide (0.75g) was added and the reaction was held at 75 °C for three more hours. The mixture was then cooled to room temperature and the solid was filtered off with vacuum. The wet cake was dried at about 80°C in a vacuum drying oven for about 24 hrs giving a white powder. The compositions prepared by the foregoing method are shown in the tables below.

Table 2-A

*The viscosity is measured at 1.0 wt% of total solids and a pH ~ 3 to 4 in water using a Brookfield RV viscometer at 20 rpm

**Turbidity at 1.0% solution in water

Table 2-B: Viscosity (cP) and varying pH

The viscosity was measured at 0.5 wt% of total solids and different pH in water using a Brookfield RV viscometer at 20 rpm Table 2-C: Viscosity (cP) and varying temperature

Viscosity was measured at 1.0 wt% of total solids at 100 s^" using a corn and plate rheometer.

Example 3 -Precipitation Co-polymer Preparation for post crosslinking

[0111] Comparative copolymers as well as inventive polymers were prepared in the same way described in Example 2. Crosslinking monomers were not added during the polymerization process; and instead, the dried polymer powders were dissolved in water (1 wt%) and the equal amount by weight of Zr (IV) acetylacetonate were dissolved under stirring. Then, the viscosities and pH of polymer solution were measured after cooling.

Table 3 -A Polymers for post crosslinking

The viscosity was measured using a Brookfie d RV viscometer at 20 rpm

The formation of the gel was monitored systematically using an AR G2, controlled-stress rheometer with a pressure cell chamber containing a concentric cylinder geometry from TA Instruments. A positive pressure between 50-100 psi was maintained using pure nitrogen. A two-step procedure was used to test the gels. During the first step, the temperature was increased from 25 to 150°C over 30 minutes at a constant shear rate of 100 s^"1. During the second step, the temperature was held at 150°C for 1 hour at the same shear rate. Table 3-B Viscosity (cP) and varying temperature

Example 4 - Two Stage Emulsion Copolymer Preperations

[0112] In a first stage, into an agitator equipped first (feed) reactor containing 224 g of deionized water and 6.4 g of sodium lauryl sulfate (30% in water by weight), 6.4 g of Calfax DB45, 40 g of of n-butyl acrylate (nBA), 394.6 g of ethyl acrylate (EA), 298.4 g of methacrylic acid (MAA) and 3.0 g of trimethylolpropane triacrylate (TMPTA) are added under nitrogen atmosphere and mixed at 500 rpm to form a monomer emulsion. To an agitator equipped second reactor are added 1 ,600 g of deionized water and 3.17 g of sodium lauryl sulfate (30 % in water by weight). The contents of the second reactor are heated with mixing agitation (200 rpm) under a nitrogen atmosphere. When the contents of the second reactor reaches a temperature of approximately 88°C, 20.5 g of ammonium persulfate solution (2.4 % in water by weight) is injected into the heated surfactant solution. The monomer emulsion from the feed reactor is gradually metered (8.44 g/min.) into the second reactor over a period of about 120 minutes at a reaction temperature maintained at approximately 88°C and allowed to react in a first stage polymerization reaction to form an ASE (Alkali swellable emulsion) core polymer particles of crosslinked n- butyl acrylate/ethyl acrylate/methacrylic acid/ trimethylolpropane triacrylate copolymer.

[0113] In a second stage(is this stage break correct?), following the initial addition of the monomer emulsion into the second reactor, the second stage monomer emulsion is prepared in the feed reactor by adding 56 g of deionized water , 1.6 g of sodium lauryl sulfate (30% in water by weight), 1.6 g of Calfax DB45, 60 g of n-butyl acrylate, 34 g of ethyl acrylate, 150 g of C_HAMPS solution (20 % in water by weight), 74.6 g of methacrylic acid, and 0.75 g of trimethylolpropane triacrylate. The monomer emulsion containing C_HAMPS is then metered into the second reactor over a period of 30 minutes at a controlled rate (15.54 g/min.) at a temperature maintained at approximately 88°C and polymerized in the presence of the ASE core polymer particles in a second stage reaction to form a crosslinked polymer shell rich in associative hydrophobes (over the ASE core polymer particles) comprising polymerized n-butyl acrylate/ ethyl acrylate/Ci₆AMPS/methacrylic acid/trimethylolpropane triacrylate copolymer. With the emulsion monomer feed, 150 g of ammonium persulfate (0.247% in water by weight) is simultaneously metered into the reaction mixture in the second reactor and the temperature of the reaction is maintained at about 88°C for an additional two and half hours to complete polymerization. The resulting polymer emulsion product is cooled to room temperature, discharged from the reactor and recovered. The core and shell monomer components are presented in Tables below. Table 4-A - First Stage Core Monomer Components

Table 4-B - Second Stage Shell Monomer Components

Table 4-C - Overall Monomer Compositions of Two Stage Emulsion Polymerization

Example 5 - One Stage Emulsion Copolymer Preparations

[0114] A single stage emulsion polymer is polymerized from the components set forth in Table 5 -A. The polymer is synthesized as set forth in Example 4 above, except that the polymerization is terminated following the first stage reaction and recovered. Table 5-A - One Stage Core Monomer Components

Example 6: Gel properties

[0115] This example describes gel properties made from the emulsion polymers of Examples 4 and 5. These gels are made as mucilages of 1 and 2.5 wt.% total polymer solids in water and neutralized to pH values ranging from 6.8 to 7.5 with

18% NaOH.

[0116] Each of the documents referred to above is incorporated herein by reference, including any prior applications, whether or not specifically listed above, from which priority is claimed. The mention of any document is not an admission that such document qualifies as prior art or constitutes the general knowledge of the skilled person in any jurisdiction. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about." It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. Similarly, the ranges and amounts for each element of the invention can be used together with ranges or amounts for any of the other elements. [0117] As used herein, the transitional term "comprising," which is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, un-recited elements or method steps. However, in each recitation of "comprising" herein, it is intended that the term also encompass, as alternative embodiments, the phrases "consisting essentially of and "consisting of," where "consisting of excludes any element or step not specified and "consisting essentially of permits the inclusion of additional un-recited elements or steps that do not materially affect the basic and novel characteristics of the composition or method under consideration.

[0118] While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. In this regard, the scope of the invention is to be limited only by the following claims.

Claims

What is claimed is:

1. A polymer comprising units derived from:

(A) a first monomer composition comprising an ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomer, where the monomer includes at least one alkyl group containing 5 to 30 carbon atoms, or salts thereof;

(B) a second monomer composition comprising one or more ethylenically unsaturated polymerizable monomers, or salts thereof;

(C) a third composition comprising one more crosslinking agents;

wherein the second monomer of (B) is different from the first monomer of (A).

2. The polymer of claim 1, wherein (B) the second monomer composition comprises:

(i) one or more ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomers where the monomers of free of any alkyl groups containing more than 4 carbon atoms or salts thereof;

(ii) one or more carboxylic acid monomers or partial esters, or salts thereof;

(iii) one or more amide monomers;

(iv) one or more alkoxylated hydrophobically modified associative monomers;

(v) one or more phosphonic acid monomers or partial esters, or salts therof;

(vi) one or more vinyl monomers; or

(vii) any combination thereof.

3. The polymer of any of the claims 1 to 2 wherein (B) comprises one or more ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomers where the monomers of free of any alkyl groups containing more than 4 carbon atoms.

4. The polymer of any of the claims 1 to 3 wherein (B) comprises a compound having the structure:

5. The polymer of any of the claims 1 to 4 wherein (B) comprises 2-acrylamido-2- methypropane-1 -sulfonic acid, a mono or multivalent metal of one or more thereof, an ammonium salt or one or more thereof, an alkylamine salt of one or more thereof or a combination thereof.

6. The polymer of any of the claims 1 to 5 wherein (B) comprises one or more ethylenically unsaturated polymerizable carboxylic acid monomers, or salts and/or esters or partial esters thereof.

7. The polymer of any of the claims 1 to 6 wherein (B) comprises acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid or salts and/or esters or partial esters thereof. 8. The polymer of any of the claims 1 to 7 wherein (B) comprises one or more acrylamide monomers.

9. The polymer of any of the claims 1 to 8 wherein (B) comprises one or more ethylenically unsaturated N-substituted carboxylic acids selected from acrylamide, methyl acrylamide, methyl methacrylamide, N-alkylmethacrylamide, N,N- dialkylmethacrylamide, N-alkylacrylamide, and N,N-dialkylacrylamide.

10. The polymer of any of the claims 1 to 9 wherein (C) comprises ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; dipentaerythritol hexa(meth)acrylate, 1 ,4-cyclohexanediol dimethyacrylate, a polyallyl ether of sucrose having from 2 to 8 allyl groups per molecule, a pentaerythritol diallyl ether, a pentaerythritol triallyl ether, a pentaerythritol tetraallyl ether, a trimethylolpropane diallyl ether, a trimethylolpropane triallyl ether, N,N'-methylenebisacrylamide, diacrylamide, l,l-bisacrylamido-2-methylpropane sulfonic acid, or any combination thereof. 11. The polymer of any of the claims 1 to 10 wherein (C) comprises one or more boron compounds, one or more polyvalent metal ions selected from the group consisting of zirconium, chromium, titanium, aluminum, and mixtures thereof, or any combination thereof. 12. The polymer of any of the claims 1 to 9 wherein the polymer further comprises units derived from:

(D) a fourth monomer composition comprising one or more monomers that include an alkyl group containing 1 to 18 carbon atoms comprising a simple ester, a vinyl ester, an mono-allyl ether, or salts thereof, or any combination thereof.

13. The polymer of any of the claims 1 to 12 wherein (A) comprises a compound having the structure:

where R 1 is an alkyl group containing from 5 to 30 carbon atoms; R 2 is hydrogen or an alkyl group containing from 1 to 30 carbon atoms; and R is an alkyl group containing 1 to 4 carbon atoms; and R⁷ is hydrogen or a methyl group;

or a metal, ammonium, or alkylamine salt thereof.

14. The polymer of any of the claims 1 to 13 wherein (A) comprises 2-acrylamido-2- dodecane sulfonic acid, 2-acrylamido-2-hexadecane sulfonic acid, 2-acrylamido-2- octadecane sulfonic acid, 2-acrylamido-2-decane sulfonic acid, 2-acrylamido-2-octane sulfonic acid, 2-acrylamido-2-diisobutane sulfonic acid, 2-acrylamido-2-heptadecane sulfonic acid, 2-acrylamido-2-pentadecane sulfonic acid, 2-acrylamido-2-decane-2- octane sulfonic acid, 2-methacrylamido-2-dodecane sulfonic acid, 2-methacrylamido-2- hexadecane sulfonic acid, 2-methacrylamido-2-octadecane sulfonic acid, 2- methacrylamido-2-decane sulfonic acid, 2-methacrylamido-2-octane sulfonic acid, 2- metacrylamido-2-hexane sulfonic acid, 2-metacrylamido-2-heptane sulfonic acid, 2- methacrylamido-2-diisobutane sulfonic acid, 2-methacrylamido-2-heptadecane sulfonic acid, 2-methacrylamido-2-pentadecane sulfonic acid, 2-methacrylamido-2-decane-2- octane sulfonic acid, an alkali metal of one or more thereof, an ammonium salt or one or more thereof, an alkylamine salt of one or more thereof, or a combination thereof.

15. The polymer of any of the claims 1 to 14 wherein the polymer is made up of:

0.1 to 50 percent by weight units derived from (A);

30 to 99.89 percent by weight units derived from (B); and

0.01 to 50 percent by weight units derived from (C).

16. The polymer of any of the claims 1 to 14 wherein the polymer is made up of:

0.1 to 50 percent by weight units derived from (A); 25 to 99.88 percent by weight units derived from (B);

0.01 to 50 percent by weight units derived from (C); and

0.01 to 5 percent by weight unites derived from (D).

17. The polymer of any of the claims 1 to 16 where the polymer is free of units derived from an alkylene glycol monomer.

18. The polymer of any of the claims 1 to 17 where the polymer units derived from the compounds of (A) have the following structures:

R⁷

R¹- -R²

R³

SO,H

wherein:

R is an alkyl group containing from 5 to 24 carbon atoms;

2

R is hydrogen or an alkyl group containing from 1 to 10 carbon atoms;

R is an alkyl group containing 1 to 4 carbon atoms;

R⁷ is hydrogen or a hydrocarbyl group;

alkali metal or ammonium salt thereof.

A process of making a polymer comprising the steps of:

(I) reacting:

(A) a first monomer composition comprising an ethylenically unsaturated hydrocarbylamidoalkanesulfonic acid monomer, where the monomer includes at least one alkyl group containing 5 to 30 carbon atoms, or salts thereof; (B) a second monomer composition comprising one or more ethylenically unsaturated polymerizable monomers, or salts thereof;

(C) a third composition comprising one more crosslinking agents; wherein the second monomer of (B) is different from the first monomer of (A).

20. The process of claim 17 wherein step (I) further comprises reacting: (D) a fourth monomer composition comprising one or more monomers that include an alkyl group containing 1 to 18 carbon atoms comprising a simple ester, a vinyl ester, an mono-allyl ether, or salts thereof, or any combination thereof; with (A), (B), and (C).

21. The use of the polymer of any of the claims 1 to 15 as a viscosifying agent in a composition and/or process.