# US 9,518,209 B2 · Solids free gellable treatment fluids > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,209 B2 - Document ID: US9518209B2 - Status: Granted - Kind: B2 - Application number: 14/891,605 - Filed: 2013-09-03 - Published: 2016-03-24 - Granted: 2016-12-13 - Earliest claimed: 2013-09-03 - Assignees: Halliburton Energy Services, Inc. - Applicants: Halliburton Energy Services, Inc. - Inventors: Pubudu H Gamage - Web page: https://patentgrep.com/patent/US9518209B2 ## CPC - C09K 8/426: {for plugging} - C09K 8/08: containing natural organic compounds, e.g. polysaccharides, or derivatives thereof - C09K 8/20: Natural organic compounds or derivatives thereof, e.g. polysaccharides or lignin derivatives - C09K 8/512: containing cross-linking agents - C09K 8/514: of natural origin, e.g. polysaccharides, cellulose (C09K8/512 takes precedence) - C09K 8/5756: {containing cross-linking agents} - C09K 8/5758: {of natural origin, e.g. polysaccharides, cellulose (C09K8/5756 takes precedence)} - C09K 8/685: {containing cross-linking agents} - C09K 8/725: {Compositions containing polymers} - C09K 8/887: {containing cross-linking agents} - C09K 8/905: {Biopolymers} - E21B 21/062: {by mixing components} - E21B 43/16: Enhanced recovery methods for obtaining hydrocarbons - 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 Gellable treatment fluids containing an amps-acrylamide bipolymer and a suitable surfactant can be used in various subterranean operations where it is necessary for the treatment fluid to remain in a gelled state for extended periods of time at high formation temperatures. The gellable treatment fluids are thermally-stable, solids-free self-degrading treatment fluid compositions useful in fluid loss pill, kill pill, perforation pill and other gel treatment applications. ## Claims ### Claim 1 A treatment fluid for a subterranean formation comprising: an aqueous carrier fluid; a crosslinking agent; an amps-acrylamide bipolymer; and a gel stabilizer comprising a first stabilizer selected from the group consisting of ascorbic acid, erythorbic acid, any salt thereof, any derivative thereof and combinations thereof, a second stabilizer selected from the group consisting of alkylhydroxylamines and combinations thereof, and a third stabilizer selected from the group consisting of sulfite salts and combinations thereof. ### Claim 2 (depends on 1) The treatment fluid of claim 1 wherein said gel stabilizer consists essentially of one or more erythorbates, one or more alkylhydroxylamines and sodium sulfite and said treatment fluid has no other gel stabilizers. ### Claim 3 (depends on 1) The treatment fluid of claim 1 wherein said amps-acrylamide bipolymer is obtained by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid monomer units and acrylamide monomer units wherein said amps-acrylamide bipolymer has a molecular weight from 7 million to 9 million. ### Claim 4 (depends on 3) The treatment fluid of claim 3 wherein said amps-acrylamide bipolymer has a molecular weight of about 8 million. ### Claim 5 (depends on 3) The treatment fluid of claim 3 wherein said treatment fluid has a composition that undergoes gellation at a formation temperature from about 225° F. to about 320° F. with the resulting gelled treatment fluid self-degrading at said formation temperature of from about 225° F. to about 320° F. in about 16 hours to 2 days. ### Claim 6 (depends on 3) The treatment fluid of claim 3 wherein said treatment fluid has a composition that undergoes gellation at a formation temperature from about 225° F. to about 300° F. with the resulting gelled treatment fluid self-degrading at said formation temperature of from 225° F. to 300° F. in from 1 day to 2 days. ### Claim 7 (depends on 3) The treatment fluid of claim 3 wherein said amps-acrylamide bipolymer consists essentially of 2-acrylamido-2-methylpropanesulfonic acid monomer units and acrylamide monomer units. ### Claim 8 (depends on 7) The treatment fluid of claim 7 wherein said gel stabilizer consists essentially of one or more erythorbates, one or more alkylhydroxylamines and sodium and said treatment fluid has no other gel stabilizers. ### Claim 9 (depends on 7) The treatment fluid of claim 7 wherein said treatment fluid has a composition that undergoes gellation at a formation temperature from about 225° F. to about 300° F. with the resulting gelled treatment fluid self degrading at said formation temperature of from about 225° F. to about 300° F. in from 1 day to 2 days. ### Claim 10 A process for formulating a kill pill for a subterranean formation, said process comprising: adding an amps-acrylamide bipolymer to an aqueous carrier fluid while mixing to produce a first mixture, wherein said amps-acrylamide bipolymer consists essentially of 2-acrylamido-2-methylpropanesulfonic acid and acrylamide monomer units; adjusting the pH of said first mixture to from 2 to 4 to produce a pH adjusted mixture; mixing in a crosslinking agent to said pH adjusted mixture to produce a second mixture; and mixing into said second mixture a gel stabilizer comprising a first stabilizer selected from the group consisting of ascorbic acid, erythorbic acid, any salt thereof, any derivative thereof and combinations thereof, a second stabilizer selected from the group consisting of alkylhydroxylamines and combinations thereof, and a third stabilizer selected from the group consisting of sulfite salts and combinations thereof. ### Claim 11 (depends on 10) The process of claim 10 wherein said gel stabilizer consists essentially of one or more erythorbates, one or more alkylhydroxylamines and sodium sulfite and said treatment fluid has no other stabilizers. ### Claim 12 (depends on 10) The process of claim 10 wherein said amps-acrylamide bipolymer is obtained by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid and acrylamide monomer units wherein said amps-acrylamide bipolymer has a molecular weight from 7 million to 9 million. ### Claim 13 A method of treating a subterranean formation, said method comprising: providing a treatment fluid comprising an aqueous carrier fluid, a crosslinking agent, an amps-acrylamide bipolymer, and a gel stabilizer, wherein said amps-acrylamide bipolymer consists essentially of 2-acrylamido-2-methylpropanesulfonic acid and acrylamide monomer units, and wherein said gel stabilizer comprises a first stabilizer selected from the group consisting of ascorbic acid, erythorbic acid, any salt thereof, any derivative thereof and combinations thereof, a second stabilizer selected from the group consisting of alkylhydroxylamines and combinations thereof, and a third stabilizer selected from the group consisting of sulfite salts and combinations thereof; introducing said treatment fluid into a subterranean formation; allowing said treatment fluid to form a gel in said subterranean formation; and breaking said gel after it has been in said subterranean formation for at least about one day. ### Claim 14 (depends on 13) The method of claim 13 wherein said gel stabilizer consists essentially of one or more erythorbates, one or more alkylhydroxylamines and sodium sulfite and said treatment fluid has no other gel stabilizers. ### Claim 15 (depends on 13) The method of claim 13 wherein said amps-acrylamide bipolymer is obtained by copolymerization of 2-acrylamido-2-methylpropanesulfonic acid and acrylamide monomer units wherein said amps-acrylamide bipolymer has a molecular weight from 7 million to 9 million. ### Claim 16 (depends on 15) The method of claim 15 wherein said treatment fluid has a composition that undergoes gellation at a formation temperature from about 225° F. to 320° F. with the resulting gelled treatment fluid self-degrading at said formation temperature of from 225° F. to about 320° F. in about 16 hours to 2 days.