# US 8,541,051 B2 · On-the fly coating of acid-releasing degradable material onto a particulate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,051 B2 - Document ID: US8541051B2 - Status: Granted - Kind: B2 - Application number: 10/736,339 - Filed: 2003-12-15 - Published: 2005-02-17 - Granted: 2013-09-24 - Earliest claimed: 2003-08-14 - Assignees: Halliburton Energy Services, Inc. - Applicants: Rajesh K. Saini; Bradley L. Todd - Inventors: Rajesh K. Saini; Bradley L. Todd - Web page: https://patentgrep.com/patent/US8541051B2 ## CPC - C09K 8/536: characterised by their form or by the form of their components, e.g. encapsulated material - C09K 8/706: {Encapsulated breakers} - C09K 8/72: Eroding chemicals, e.g. acids - C09K 8/805: {Coated proppants} - E21B 43/04: Gravelling of wells - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract The present invention relates to methods and compositions for treating subterranean formations, and more specifically, to improved methods and compositions for degrading filter cake deposited on a subterranean formation. One embodiment of the present invention provides a method of creating particulates coated with acid-releasing degradable material on-the-fly comprising the step of: combining an acid-releasing degradable material with a solvent or a plasticizer to create a coating solution; and, coating the coating solution onto a particulate on-the-fly to create coated particulates. Another embodiment of the present invention provides a gravel pack comprising gravel particles coated on-the-fly with an acid-releasing degradable material. ## Claims ### Claim 1 A method of degrading filter cake in a subterranean formation comprising the steps of: combining an acid-releasing degradable material with a solvent or a plasticizer to create a coating solution, wherein the acid-releasing degradable material comprises at least one acid-releasing degradable material selected from the group consisting of: poly(orthoester); a lactide, a poly(lactide); a glycolide; a poly(glycolide); a poly(ε-caprolactone); a poly(hydroxybutyrate); a substantially water insoluble anhydride; a poly(anhydride); a poly(amino acid); a copolymer of two or more of the above-listed compounds; and any combination thereof; coating the coating solution onto a particulate on-the-fly to create coated particulates, wherein the acid-releasing degradable material comprises a material that is substantially water insoluble; placing the coated particulates into a subterranean formation so that at least a portion of the coated particulates become incorporated in a pack substantially adjacent to a filter cake; allowing the acid-releasing degradable material to produce acid; and allowing the acid to contact and degrade a portion of the filter cake. ### Claim 2 (depends on 1) The method of claim 1 wherein the filter cake comprises a filter cake on the walls of a well bore or a filter cake on the walls of a fracture. ### Claim 3 (depends on 1) The method of claim 1 wherein the particulates are coated with from about 0.1% to about 20% acid-releasing degradable material by weight of the particulates. ### Claim 4 (depends on 1) The method of claim 1 wherein acid-releasing degradable material comprises a material that degrades over time in an aqueous environment. ### Claim 5 (depends on 1) The method of claim 1 wherein the solvent comprises at least one solvent selected from the group consisting of: acetone; propylene carbonate; di(propylene glycol) methyl ether; di(propylene glycol) propyl ether; di(propylene glycol) butyl ether; di(propylene glycol) methyl ether acetate; isopropyl alcohol; chloroform; dichloromethane; trichloromethane; 1,2-dichlorobenzene; tetrahydrofuran; benzene; acetonitrile; dioxane; dimethylformamide; toluene; ethyl acetate; isoamyl alcohol; N-methylpyrrolidone; xylene; dichloroacetic acid; m-cresol; hexafluoroisopropanol; diphenyl ether; acetonitrile; methanol; ethyl benzene; naphthalene; naphtha; and any combination thereof. ### Claim 6 (depends on 1) The method of claim 1 wherein the plasticizer comprises at least one plasticizer selected from the group consisting of: polyethylene glycol; polyethylene oxide; oligomeric lactic acid; a citrate ester; a glucose monoester; a partially esterified fatty acid ester; PEG monolaurate; triacetin; poly(ε-caprolactone); poly(hydroxybutyrate); glycerin-1-benzoate-2,3-dilaurate; glycerin-2-benzoate-1,3-dilaurate; a starch; bis(butyl diethylene glycol)adipate; ethylphthalylethyl glycolate; glycerine diacetate monocaprylate; diacetyl monoacyl glycerol; polypropylene glycol; poly(propylene glycol)dibenzoate, dipropylene glycol dibenzoate; glycerol; ethyl phthalyl ethyl glycolate; poly(ethylene adipate)distearate; di-iso-butyl adipate; and any combination thereof. ### Claim 7 (depends on 1) The method of claim 1 wherein the acid-releasing degradable material comprises a poly(orthoester). ### Claim 8 A method of using a portion of a gravel pack to degrade a portion of a filter cake comprising the steps of: combining an acid-releasing degradable material with a solvent or a plasticizer to create a coating solution; wherein the acid-releasing degradable material comprises at least one acid-releasing degradable material selected from the group consisting of: poly(orthoester); a poly(ε-caprolactone); a poly(hydroxybutyrate); a substantially water insoluble anhydride; a poly(anhydride); a poly(amino acid); a copolymer of two or more of the above-listed compounds; and any combination thereof; coating the coating solution onto gravel on-the-fly to create coated gravel, wherein the acid-releasing degradable material comprises a material that is substantially water insoluble; introducing the coated gravel to a well bore having a filter cake so that at least a portion of the coated gravel is incorporated in a gravel pack substantially adjacent to the filter cake; allowing the acid-releasing degradable material to produce acid; and, allowing the acid to contact and degrade a portion of the filter cake. ### Claim 9 (depends on 8) The method of claim 8 wherein the gravel pack composition comprises from about 0.1% to about 20% acid-releasing degradable material by weight of the gravel particles. ### Claim 10 (depends on 8) The method of claim 8 wherein the acid-releasing degradable material comprises a material that it degrades over time. ### Claim 11 (depends on 8) The method of claim 8 wherein the solvent comprises at least one solvent selected from the group consisting of: acetone; propylene carbonate; di(propylene glycol) methyl ether; di(propylene glycol) propyl ether; di(propylene glycol) butyl ether; di(propylene glycol) methyl ether acetate; isopropyl alcohol; chloroform; dichloromethane; trichloromethane; 1,2-dichlorobenzene; tetrahydrofuran; benzene; acetonitrile; dioxane; dimethylformamide; toluene; ethyl acetate; isoamyl alcohol; N-methylpyrrolidone; xylene; dichloroacetic acid; m-cresol; hexafluoroisopropanol; diphenyl ether; acetonitrile; methanol; ethyl benzene; naphthalene; naphtha; and any combination thereof. ### Claim 12 (depends on 8) The method of claim 8 wherein the plasticizer comprises at least one plasticizer selected from the group consisting of: polyethylene glycol; polyethylene oxide; oligomeric lactic acid; a citrate ester; a glucose monoester; a partially esterified fatty acid ester; PEG monolaurate; triacetin; poly(ε-caprolactone); poly(hydroxybutyrate); glycerin-1-benzoate-2,3-dilaurate; glycerin-2-benzoate-1,3-dilaurate; a starch; bis(butyl diethylene glycol)adipate; ethylphthalylethyl glycolate; glycerine diacetate monocaprylate; diacetyl monoacyl glycerol; polypropylene glycol; poly(propylene glycol)dibenzoate, dipropylene glycol dibenzoate; glycerol; ethyl phthalyl ethyl glycolate; poly(ethylene adipate)distearate; di-iso-butyl adipate; and any combination thereof. ### Claim 13 (depends on 8) The method of claim 8 wherein the acid-releasing degradable material comprises a poly(orthoester). ### Claim 14 A method of degrading filter cake in a subterranean formation comprising the steps of: combining an acid-releasing degradable material with a plasticizer to create a coating solution, with the proviso that the plasticizer does not comprise a starch; coating the coating solution onto a particulate on-the-fly to create coated particulates, wherein the acid-releasing degradable material comprises a material that is substantially water insoluble; placing the coated particulates into a subterranean formation so that at least a portion of the coated particulates become incorporated in a pack substantially adjacent to a filter cake; allowing the acid-releasing degradable material to produce acid; and allowing the acid to contact and degrade a portion of the filter cake. ### Claim 15 (depends on 14) The method of claim 14 wherein the filter cake comprises a filter cake on the walls of a well bore or a filter cake on the walls of a fracture. ### Claim 16 (depends on 14) The method of claim 14 wherein the particulates are coated with from about 0.1% to about 20% acid-releasing degradable material by weight of the particulates. ### Claim 17 (depends on 14) The method of claim 14 wherein acid-releasing degradable material comprises a material that degrades over time in an aqueous environment. ### Claim 18 (depends on 14) The method of claim 14 wherein the acid-releasing degradable material comprises at least one acid-releasing degradable material selected from the group consisting of: a polyester, a poly(orthoester); a lactide, a poly(lactide); a glycolide; a poly(glycolide); a poly(ε-caprolactone); a poly(hydroxybutyrate); a substantially water insoluble anhydride; a poly(anhydride); a poly(amino acid); a mixture of one of the above-listed compounds; a copolymer of two or more of the above-listed compounds; and any combination thereof. ### Claim 19 (depends on 14) The method of claim 14 wherein the plasticizer comprises at least one plasticizer selected from the group consisting of: polyethylene glycol; polyethylene oxide; oligomeric lactic acid; a citrate ester; a glucose monoester; a partially esterified fatty acid ester; PEG monolaurate; triacetin; poly(ε-caprolactone); poly(hydroxybutyrate); glycerin-1-benzoate-2,3-dilaurate; glycerin-2-benzoate-1,3-dilaurate; a starch; bis(butyl diethylene glycol)adipate; ethylphthalylethyl glycolate; glycerine diacetate monocaprylate; diacetyl monoacyl glycerol; polypropylene glycol; poly(propylene glycol)dibenzoate, dipropylene glycol dibenzoate; glycerol; ethyl phthalyl ethyl glycolate; poly(ethylene adipate)distearate; di-iso-butyl adipate; and any combination thereof. ### Claim 20 (depends on 14) The method of claim 14 wherein the acid-releasing degradable material comprises a poly(orthoester).