# US 8,739,871 B2 · Thermally-activated, high temperature particulate suspending agents and methods relating thereto > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,739,871 B2 - Document ID: US8739871B2 - Status: Granted - Kind: B2 - Application number: 13/622,005 - Filed: 2012-09-18 - Published: 2014-03-20 - Granted: 2014-06-03 - Earliest claimed: 2012-09-18 - Assignees: Halliburton Energy Services, Inc. - Applicants: Halliburton Energy Services, Inc. - Inventors: Gary P. Funkhouser - Web page: https://patentgrep.com/patent/US8739871B2 ## CPC - C09K 8/40: Spacer compositions, e.g. compositions used to separate well-drilling from cementing masses - C04B 28/02: containing hydraulic cements other than calcium sulfates - C09K 8/12: containing synthetic organic macromolecular compounds or their precursors - C09K 8/424: {using "spacer" compositions} - C09K 8/467: containing additives for specific purposes - C09K 8/68: containing organic compounds - C09K 8/70: characterised by their form or by the form of their components, e.g. foams - C09K 2208/18: Bridging agents, i.e. particles for temporarily filling the pores of a formation; Graded salts - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE ## Abstract A particulate suspending agent may be useful for mitigating particulate settling in wellbore applications with high-temperature and/or at near-neutral and higher pH values. Methods of treating a wellbore may include providing a treatment fluid comprising an aqueous liquid, a plurality of particulates, and a particulate suspending agent, wherein the particulate suspending agent comprises a crosslinked polymer particulate formed by a reaction comprising a first monofunctional monomer and an orthoester crosslinker, the orthoester crosslinker comprising an orthoester linkage and at least two crosslinking moieties; and placing the treatment fluid in a wellbore penetrating a subterranean formation. ## Claims ### Claim 1 A method comprising: providing a treatment fluid comprising an aqueous liquid, a plurality of particulates, and a particulate suspending agent, wherein the particulate suspending agent comprises a crosslinked polymer particulate formed by a reaction comprising a first monofunctional monomer and an orthoester crosslinker, the orthoester crosslinker comprising an orthoester linkage and at least two crosslinking moieties; and placing the treatment fluid in a wellbore penetrating a subterranean formation. ### Claim 2 (depends on 1) The method of claim 1, wherein the treatment fluid is a spacer fluid. ### Claim 3 (depends on 1) The method of claim 1, wherein the treatment fluid has a pH between about 5 and about 8. ### Claim 4 (depends on 1) The method of claim 1, wherein the treatment fluid has a pH of about 8 or greater. ### Claim 5 (depends on 1) The method of claim 1, wherein the plurality of particulates comprise at least one selected from the group consisting of a hydraulic cement, a weighting agent, a proppant, a fine aggregate particulate, and any combination thereof. ### Claim 6 (depends on 1) The method of claim 1, wherein the subterranean formation is about 150° F. to about 500° F. ### Claim 7 (depends on 1) The method of claim 1, wherein the crosslinked polymer particulate begins to degrade and dissolve above about 150° F. ### Claim 8 (depends on 1) The method of claim 1, wherein the first monofunctional monomer comprises a monomer selected from the group consisting of acrylamide, an N-substituted acrylamide, an N,N-disubstituted acrylamide, an N-vinylamide, an N-alkyl-N-vinylamide, N,N-dimethylacrylamide, sodium 2-acrylamido-2-methylpropanesulfonate, 2-acrylamido-2-methylpropanesulfonic acid, N-(hydroxymethyl)acrylamide, N-(hydroxyethyl)acrylamide, methacrylamide, N-vinylformamide, 1-vinyl-2-pyrrolidinone, N-vinylcaprolactam, N-acryloyl morpholine, N-methyl-N-vinylacetamide, N-isopropylacrylamide, N,N-diethylacrylamide, N-vinylacetamide, acrylic acid, sodium 4-styrenesulfonate, vinylsulfonic acid, and any derivative thereof. ### Claim 9 (depends on 1) The method of claim 1, wherein the orthoester crosslinker is present in the reaction at about 0.1% to about 20% by weight of total monomer. ### Claim 10 (depends on 1) The method of claim 1, wherein the reaction further comprises a second monofunctional monomer, wherein the second monofunctional monomer and the first monofunctional monomer are different. ### Claim 11 (depends on 10) The method of claim 10, wherein the weight ratio of the first monofunctional monomer to the second monofunctional monomer in the reaction ranges from about 0.1:99.9 to about 99.9:0.1. ### Claim 12 A treatment fluid comprising: an aqueous fluid, a plurality of particulates, and a particulate suspending agent comprising a crosslinked polymer particulate, wherein the crosslinked polymer particulate is produced from a reaction comprising: a first monofunctional monomer, and an orthoester crosslinker that comprises an orthoester linkage and at least two crosslinking moieties. ### Claim 13 (depends on 12) The treatment fluid of claim 12, wherein the plurality of particulates comprise at least one selected from the group consisting of a hydraulic cement, a weighting agent, a proppant, a fine aggregate particulate, and any combination thereof. ### Claim 14 (depends on 12) The treatment fluid of claim 12, wherein the reaction further comprises a second monofunctional monomer, wherein the first monofunctional monomer and the second monofunctional monomer are different. ### Claim 15 (depends on 12) The treatment fluid of claim 12, wherein the treatment fluid has a pH between about 5 and about 8. ### Claim 16 A method comprising: providing a treatment fluid comprising an aqueous liquid, a plurality of particulates, and a particulate suspending agent, wherein the particulate suspending agent comprises a crosslinked polymer particulate that comprises a polymer crosslinked with an orthoester crosslinker that comprises an orthoester linkage and at least two crosslinking moieties; placing the treatment fluid in a wellbore penetrating a subterranean formation with a bottom hole static temperature of about 150° F. or greater; and allowing the orthoester linkage to degrade thereby allowing at least some of the polymer to dissolve and suspend the particulates. ### Claim 17 (depends on 16) The method of claim 16, wherein the treatment fluid is selected from the group consisting of a cement slurry, a flush fluid, a spacer fluid, and a fracturing fluid. ### Claim 18 (depends on 16) The method of claim 16, wherein the polymer comprises a first monofunctional monomer that comprises a monomer selected from the group consisting of acrylamide, an N-substituted acrylamide, an N,N-disubstituted acrylamide, an N-vinylamide, an N-alkyl-N-vinylamide, N,N-dimethylacrylamide, sodium 2-acrylamido-2-methylpropanesulfonate, 2-acrylamido-2-methylpropanesulfonic acid, N-(hydroxymethyl)acrylamide, N-(hydroxyethyl)acrylamide, methacrylamide, N-vinylformamide, 1-vinyl-2-pyrrolidinone, N-vinylcaprolactam, N-acryloyl morpholine, N-methyl-N-vinylacetamide, N-isopropylacrylamide, N,N-diethylacrylamide, N-vinylacetamide, acrylic acid, sodium 4-styrenesulfonate, vinylsulfonic acid, and any derivative thereof. ### Claim 19 (depends on 16) The method of claim 16, wherein the treatment fluid has a pH between about 5 and about 8. ### Claim 20 A method of producing a particulate suspending agent, the method comprising: providing an oil solution comprising an oil-based solvent and a surfactant; providing a monomer mixture comprising an aqueous liquid and a first monofunctional monomer; forming an inverse suspension with the monomer mixture and the oil solution; reacting the monomer mixture in the inverse suspension with a free-radical initiator to form a polymer particulate; isolating the polymer particulate; and diffusing an orthoester crosslinker into the polymer particulate so as to form a crosslinked polymer particulate.