US 11,840,662 B2
Development of ultra-high molecular weight (UHMW) branched block copolymer shale inhibitor for water based drilling fluid
Sivaprakash Shanmugam, Houston, TX (US); Ashok Santra, The Woodlands, TX (US); and Carl Thaemlitz, Cypress, TX (US)
Assigned to SAUDI ARABIAN OIL COMPANY, Dhahran (SA)
Filed by ARAMCO SERVICES COMPANY, Houston, TX (US)
Filed on Feb. 4, 2022, as Appl. No. 17/650,004.
Claims priority of provisional application 63/145,576, filed on Feb. 4, 2021.
Prior Publication US 2022/0243116 A1, Aug. 4, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C09K 8/12 (2006.01); C09K 8/528 (2006.01)
CPC C09K 8/528 (2013.01) [C09K 8/12 (2013.01)] 7 Claims
 
1. A drilling fluid composition comprising:
a base fluid; and
a shale inhibitor comprising a branched multi-block polymer having the following structure,

OG Complex Work Unit Chemistry
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.