# US 7,608,567 B2 · Degradable surfactants and methods for use > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,567 B2 - Document ID: US7608567B2 - Status: Granted - Kind: B2 - Application number: 11/127,583 - Filed: 2005-05-12 - Published: 2006-11-16 - Granted: 2009-10-27 - Earliest claimed: 2005-05-12 - Assignees: Halliburton Energy Services, Inc. - Inventors: Rajesh K. Saini - Web page: https://patentgrep.com/patent/US7608567B2 ## CPC - C09K 8/12: containing synthetic organic macromolecular compounds or their precursors - C09K 8/28: containing organic additives - C09K 8/36: Water-in-oil emulsions - C09K 8/38: Gaseous or foamed well-drilling compositions - C09K 8/52: Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning - C09K 8/604: {Polymeric surfactants} - C09K 8/68: containing organic compounds - C09K 8/703: {Foams} - C09K 8/94: Foams - C10L 1/328: {Oil emulsions containing water or any other hydrophilic phase} - Y10S 507/922: Fracture fluid - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract The present invention relates to methods for treating subterranean formations. A method, that comprises providing a treatment fluid that comprises an aqueous fluid, and a degradable surfactant derived from a degradable polymer; and introducing the treatment fluid into a well bore that penetrates the subterranean formation, is provided. ## Claims ### Claim 1 A method of treating a subterranean formation, comprising: providing a treatment fluid comprising an aqueous fluid and a degradable surfactant derived from a degradable polymer, wherein the degradable surfactant is not a phosphate ester and wherein the degradable surfactant has a hydrophilic/lipophilic balance that facilitates the formation of an emulsion; and introducing the treatment fluid into a well bore that penetrates the subterranean formation. ### Claim 2 (depends on 1) The method of claim 1 wherein the degradable surfactant comprises a degradable block copolymer surfactant that comprises a hydrophilic polymeric block and a hydrophobic degradable polymeric block. ### Claim 3 (depends on 2) The method of claim 2 wherein the degradable block copolymer surfactant comprises a hydrophilic polymeric backbone grafted with a polylactic acid or a poly(caprolactone). ### Claim 4 (depends on 3) The method of claim 3 wherein the hydrophilic polymeric block comprises guar. ### Claim 5 (depends on 2) The method of claim 2 wherein the degradable block copolymer surfactant comprises a block copolymer of a poly(alkylene glycol) or a poly(alkylene oxide), and an aliphatic polyester. ### Claim 6 (depends on 2) The method of claim 2 wherein the degradable block copolymer surfactant comprises a quaternary ammonium degradable block copolymer salt. ### Claim 7 (depends on 1) The method of claim 1 wherein the degradable surfactant comprises a degradable polymeric surfactant that comprises an aliphatic polyester tail and a hydrophilic head group. ### Claim 8 (depends on 7) The method of claim 7 wherein the degradable polymeric surfactant is formed from a reaction that comprises at least one of the following: a poly(anhydride); a poly(orthoester); a poly(lactic acid); a poly(glycolic acid); a poly(caprolactone); a poly(hydroxybutyrate); a polyphosphazine; a poly(carbonate); a polyacetal; a polyetherester; a polyesteramide; a polycyanoacrylate; a polyurethane; a polyacrylate; or a copolymer thereof. ### Claim 9 (depends on 7) The method of claim 7 wherein the degradable polymeric surfactant comprises a quaternary amine cationic surfactant. ### Claim 10 (depends on 7) The method of claim 7 wherein the hydrophilic head group is an anionic group, a cationic group, an amphoteric group, a Zwifferionic group, or a non-ionic group. ### Claim 11 (depends on 7) The method of claim 7 wherein the degradable polymeric surfactant comprises poly(lactic) acid or poly(caprolactone) with a head group that comprises a salt of a carboxylic acid. ### Claim 12 (depends on 7) The method of claim 7 wherein at least a portion of the degradable polymeric surfactant has the following formula: wherein R1 is a hydrogen, an alkyl, an aryl, an alkylaryl, an acetyl, or a heteroatom; R2 is a hydrogen, an alkyl, an aryl, an alkylaryl, an acetyl, or a heteroatom, R3 is a hydrogen, an alkyl, an aryl, an alkylaryl, an acetyl, an alkoxyl, a benzoyl, a heteroatom or a group comprising an anionic group, a cationic group, or a non-ionic group; R4 is a H, a Na, a K, or a Li, or a group comprising an anionic group, a cationic group, or a non-ionic group; n is 0 or 1; m is an integer between 1 and 20; and X is an integer between 10 and 10,000. ### Claim 13 (depends on 1) The method of claim 1 wherein the treatment fluid is introduced into the well bore at a pressure sufficient to create or enhance at least one fracture in the subterranean formation. ### Claim 14 (depends on 1) The method of claim 1 wherein the hydrophilic/lipophilic balance is from about 3 to about 6 or from about 8 to about 18. ### Claim 15 (depends on 1) The method of claim 1 wherein the degradable surfactant comprises a degradable hydrophobic block attached to a hydrophilic polymeric block, the degradable hydrophobic block comprising at least one compound selected from the group consisting of: a poly(anhydride); a poly(orthoester); a poly(lactic acid); a poly(glycolic acid); a poly(caprolactone); a poly(hydroxybutyrate); a polyphosphazine; a poly(carbonate); a polyacetal; a polyetherester; a polyesteramide; a polycyanoacrylate; a polyurethane; a polyacrylate; and a copolymer thereof, the hydrophilic polymeric block comprising at least one compound selected from the group consisting of: a poly(alkylene glycol); a poly(alcohol); poly(vinyl pyrrolidone); a polysaccharide; a chitin; a chitosan; a protein; a poly(amino acid); a poly(alkylene oxide); a poly(amide); a poly(acid); a polyol; and a copolymer thereof. ### Claim 16 A method of treating a subterranean formation penetrated by a well bore comprising: providing an emulsified treatment fluid comprising an oleaginous phase, an aqueous phase, and an emulsifying agent comprising a degradable surfactant derived from a degradable polymer, wherein the degradable surfactant is not a phosphate ester; and introducing the emulsified treatment fluid into the well bore. ### Claim 17 (depends on 16) The method of claim 16 wherein the degradable surfactant comprises a degradable block copolymer surfactant that comprises a hydrophilic polymeric block and a hydrophobic degradable polymeric block. ### Claim 18 (depends on 17) The method of claim 17 wherein the degradable block copolymer surfactant comprises a block copolymer of a poly(alkylene glycol) or a poly(alkylene oxide), and an aliphatic polyester. ### Claim 19 (depends on 16) The method of claim 16 wherein the degradable surfactant has a hydrophilic/lipophilic balance of from about 3 to about 6 or from about 8 to about 18. ### Claim 20 (depends on 16) The method of claim 16 wherein the degradable surfactant comprises a degradable hydrophobic block attached to a hydrophilic polymeric block, the degradable hydrophobic block comprising at least one compound selected from the group consisting of: a poly(anhydride); a poly(orthoester); a poly(lactic acid); a poly(glycolic acid); a poly(caprolactone); a poly(hydroxybutyrate); a polyphosphazine; a poly(carbonate); a polyacetal; a polyetherester; a polyesteramide; a polycyanoacrylate; a polyurethane; a polyacrylate; and a copolymer thereof, the hydrophilic polymeric block comprising at least one compound selected from the group consisting of: a poly(alkylene glycol); a poly(alcohol); poly(vinyl pyrrolidone); a polysaccharide; a chitin; a chitosan; a protein; a poly(amino acid); a poly(alkylene oxide); a poly(amide); a poly(acid); a polyol; and a copolymer thereof. ### Claim 21 A method of treating a subterranean formation penetrated by a well bore comprising: providing a foamed treatment fluid comprising an aqueous fluid, a gas, and a foaming agent comprising a degradable surfactant derived from a degradable polymer, wherein the degradable surfactant is not a phosphate ester and wherein the degradable surfactant has a hydrophilic/lipophilic balance that facilitates the formation of an emulsion; and introducing the foamed treatment fluid into the well bore. ### Claim 22 (depends on 21) The method of claim 21 wherein the degradable surfactant comprises a degradable block copolymer surfactant that comprises a hydrophilic polymeric block and a hydrophobic degradable polymeric block. ### Claim 23 (depends on 22) The method of claim 22 wherein the degradable block copolymer surfactant comprises a block copolymer of a poly(alkylene glycol) or a poly(alkylene oxide), and an aliphatic polyester. ### Claim 24 (depends on 21) The method of claim 21 wherein the hydrophilic/lipophilic balance is from about 3 to about 6 or from about 8 to about 18. ### Claim 25 (depends on 21) The method of claim 21 wherein the degradable surfactant comprises a degradable hydrophobic block attached to a hydrophilic polymeric block, the degradable hydrophobic block comprising at least one compound selected from the group consisting of: a poly(anhydride); a poly(orthoester); a poly(lactic acid); a poly(glycolic acid); a poly(caprolactone); a poly(hydroxybutyrate); a polyphosphazine; a poly(carbonate); a polyacetal; a polyetherester; a polyesteramide; a polycyanoacrylate; a polyurethane; a polyacrylate; and a copolymer thereof, the hydrophilic polymeric block comprising at least one compound selected from the group consisting of: a poly(alkylene glycol); a poly(alcohol); poly(vinyl pyrrolidone); a polysaccharide; a chitin; a chitosan; a protein; a poly(amino acid); a poly(alkylene oxide); a poly(amide); a poly(acid); a polyol; and a copolymer thereof.