Development of ultra-high molecular weight (UHMW) branched block copolymer shale inhibitor for water based drilling fluid

1. A drilling fluid composition comprising:

a base fluid; and

a shale inhibitor comprising a branched multi-block polymer having the following structure,

where “Z” is selected from the group consisting of a hydrogen, chlorine, sulfur, oxygen, a substituted or unsubstituted alkyl or substituted or unsubstituted aryl radical, a substituted or unsubstituted heterocycle, a substituted or unsubstituted alkylthio radical, a substituted or unsubstituted arylthio radical, a substituted or unsubstituted alkylselenium radical, a substituted or unsubstituted arylselenium radical, a substituted or unsubstituted alkoxy radical, a substituted or unsubstituted aryloxy radical, a substituted or unsubstituted amino radical, a substituted or unsubstituted hydrazine radical, a substituted or unsubstituted alkoxycarbonyl radical, a substituted or unsubstituted aryloxycarbonyl radical, a substituted or unsubstituted acycloxy or carboxyl radical, a substituted or unsubstituted aroyloxy radical, a substituted or unsubstituted carbamoyl radical, a cyano radical, a dialkyl- or diarylphosphonato radical, a dialkyl-phosphinato or diaryl-phosphinato radical, and a polymer chain;

where “R′” is a substituted or unsubstituted alkyl, a substituted or unsubstituted acyl, a substituted or unsubstituted aryl, a substituted or unsubstituted aralkyl, a substituted or unsubstituted alkenyl or a substituted or unsubstituted alkynyl group; a saturated or unsaturated aromatic, a substituted or unsubstituted carbocycle or a substituted or unsubstituted heterocycle, and a polymer chain, where the polymer chain is hydrophilic;

where “A” is selected from the group consisting of (meth)acrylate monomer units carrying a COOH or COO— group, fumaric acid or monoethylenically unsaturated C4-C10 and C4-C6 dicarboxylic acid monoesters, ((meth)acrylate/(meth)acrylamide) units having phosphate, phosphonate or phosphinate groups, and sulfonic acid or sulfonate functional group;

“B” is selected from the group consisting of (meth)acrylate monomer units carrying a COOH or COO— group, unsaturated C4-C10 and C4-C6 dicarboxylic acid monoesters, ((meth)acrylate/(meth)acrylamide) units having phosphate, phosphonate or phosphinate groups, and sulfonic acid or sulfonate functional group;

“C” is selected from the group consisting of acrylamide, meth(acrylate) and meth(acrylamide) monomers with ammonium groups, meth(acrylate) and meth(acrylamide) with C20-C30 alkane diols or poly(ethylene glycol), 2-chloroethyl (meth)acrylate, tetrahydrofurfuryl acrylate, vinylacetamide, vinylpyrrolidone, N-vinyl piperidone, N-vinyl caprolactam, N-vinyl-5-methyl-2-pyrrolidone, N-vinyl-5-ethyl-2-pyrrolidone, N-vinyl-6-methyl-2-piperidone, N-vinyl-6-ethyl-2-piperidone, N-vinyl-7-methyl-2-caprolactam, and N-vinyl-7-ethyl-2-caprolactam;

“D” being selected from the group consisting of vinyl aromatic, (meth)acrylate, and (meth)acrylamide crosslinkers;

where “t” is from 3-500 units, “u”, “v”, and “w” are from 3-260000 units, and “m” and “n” are from 1-10 units.

2. The composition of claim 1 , wherein the COOH or COO— group comprises one or more selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, and aconitic acid.

3. The composition of claim 1 , wherein the fumaric acid or monoethylenically unsaturated C4-C10 and C4-C6 dicarboxylic acid monoesters comprises monomethyl maleate.

4. The composition of claim 1 , wherein the ((meth)acrylate/(meth)acrylamide) units having phosphate, phosphonate or phosphinate groups comprises one or more selected from the group consisting of such as 2-acrylamido-ethylphosphonic acid (AEPA), monoacryloyloxyethyl phosphate or bis(2-methacryloyloxyethyl) phosphate units, vinylphosphonic acid, allylphosphonic acid, isopropylphosphonic acid, diallylaminomethylene phosphonate, and respective salts.

5. The composition of claim 1 , wherein the sulfonic acid or sulfonate functional group comprises one or more selected from the group consisting of 3-sulfopropyl(meth)acrylate, 2-propene-1-sulfonic acid, sodium-1-allyloxy-2 hydroxypropylsulfonate (COPS1), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), (meth)allyl sulfonate, sodium vinylsulfonate, and sodium styrenesulfonate.

6. The composition of claim 1 , wherein the acrylamide comprises one or more selected from the group consisting of N,N-(Dimethyl acrylamide) (DMA), (meth)acrylamide, morpholine N-oxide acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethylacryl amide, (meth)acrylamide, N-isopropyl (meth)acrylamide, N-tert-butyl(meth)acrylamide, and diacetone acrylamide, meth(acrylate) and meth(acrylamide) monomers with ammonium groups selected from group consisting of N,N-dimethylaminomethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N,N-diethylaminopropyl (meth)acrylate and N,N-dimethylaminocyclohexyl (meth)acrylate; N-[2-(dimethylamino) ethyl] (meth)acrylamide, N-[3-(dimethylamino) propyl] (meth)acrylamide, N[4-(dimethylamino) butyl] (meth)acrylamide, N[2-(diethylamino) ethyl] (meth)acrylamide, and N-[4-(dimethylamino) cyclohexyl] (meth)acrylamide, [2-((Meth)acryloyloxy)ethyl] trimethylammonium chloride, N-(3-Sulfopropyl)-N-(meth)acroyloxyethyl-N,N-dimethylammonium betaine, N-(3-sulfopropyl)-N-methacroylamidepropyl-N,N-dimethylammonium betaine, N-(3-carboxymethyl)-N-methacroylamidepropyl-N,N-dimethylammonium betaine, and N-carboxymethyl-N-methacroyloxyethyl-N,N dimethylammonium betaine, and meth(acrylate) and meth(acrylamide) with C20-C30 alkane diols or poly(ethylene glycol) monomer selected from group consisting of 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate, 3-hydroxy-2-ethylhexyl(meth)acrylate, N-(hydroxymethyl)acrylamide, N-(2-hydroxypropyl)methacrylamide, N-hydroxyethylacrylamide, N-[tris(hydroxymethyl) methacrylamide, 4-acryloylmorpholine, 2-N-morpholinoethyl methacrylate, (meth)acrylate of polyethylene glycol, (meth)acrylate of diethylene glycol, ethylene glycol methyl ether (meth) acrylate, poly (propylene glycol) acrylate, 2-chloroethyl (meth)acrylate, and tetrahydrofurfuryl acrylate.

7. The composition of claim 1 , wherein the vinyl aromatic, (meth)acrylate, and (meth)acrylamide crosslinkers comprises one or more selected from the group consisting of N,N-methylenebisacrylamide, bis(2-methacryloyl)oxyethyl disulfide, 1,4-Bis(4-vinylphenoxy)butane, divinyl benzene, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetra(ethylene glycol) diacrylate triethylene glycol dimethacrylate, poly(ethylene glycol) di(meth)acrylate with a number average molecular weight of Mn=250-20000 g/mol, neopentyl glycol diacrylate, neopentyl glycol propoxylate diacrylate, and tri(propylene glycol) diacrylate.