# US 10,308,862 B2 · Compositions and methods for enhanced fracture cleanup using redox treatment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,862 B2 - Document ID: US10308862B2 - Status: Granted - Kind: B2 - Application number: 16/039,966 - Filed: 2018-07-19 - Published: 2018-11-08 - Granted: 2019-06-04 - Earliest claimed: 2014-04-17 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Ayman R. Al-Nakhli; Hazim H. Abass; Ahmad S. Al-Otaibi - Web page: https://patentgrep.com/patent/US10308862B2 ## CPC - C09K 8/536: characterised by their form or by the form of their components, e.g. encapsulated material - C09K 8/524: organic depositions, e.g. paraffins or asphaltenes - C09K 8/528: inorganic depositions, e.g. sulfates or carbonates - C09K 8/532: Sulfur - E21B 36/008: {using chemical heat generating means} - E21B 37/00: Methods or apparatus for cleaning boreholes or wells (E21B21/00 takes precedence) - C09K 2208/32: Anticorrosion additives - E21B 43/267: reinforcing fractures by propping - 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 A cleanup fluid for reducing a viscosity of a residual viscous material in fractures of a hydrocarbon-bearing formation. The cleanup fluid includes an exothermic reaction component operable to generate heat, where the heat is operable to reduce a viscosity of the residual viscous material to create a reduced viscosity material, the reduced viscosity material operable to flow from the fractures. ## Claims ### Claim 1 A method for use of a cleanup fluid in a wellbore disposed in a reservoir, the method comprising the steps of: preparing an exothermic reaction component operable to generate heat, and the exothermic reaction component comprising at least one component selected from the group consisting of: urea; sodium hypochlorite; ammonium chloride; ammonium bromide; ammonium nitrate; ammonium sulfate; ammonium carbonate; ammonium hydroxide; sodium nitrite; potassium nitrite; and mixtures thereof, where the cleanup fluid comprises only liquid components in solution prepared to be fluidly compatible with a viscous fluid component, where the cleanup fluid does not include viscosifying components at concentrations that generate foam or introduce foam into the wellbore; injecting the exothermic reaction component into the wellbore; allowing the exothermic reaction component to react in situ to produce heat and nitrogen gas, the heat and nitrogen gas operable to increase temperature and pressure in situ, to create a reduced viscosity material; and squeezing the exothermic reaction component into the reservoir by injecting a foamed material comprising a foamed brine solution into the wellbore after the step of injecting the exothermic reaction component into the wellbore, the foamed brine solution prepared from a non-foamed brine to reduce a pressure gradient of the non-foamed brine. ### Claim 2 (depends on 1) The method according to claim 1, where the exothermic reaction component and foamed material are used in a volume ratio of about 1 to 1. ### Claim 3 (depends on 1) The method according to claim 1, where the foamed brine solution reduces hydrostatic pressure of a column of the foamed brine solution by at least about 40% relative to a column of the non-foamed brine of the same size. ### Claim 4 (depends on 1) The method according to claim 1, where the foamed brine solution comprises at least one component selected from the group consisting of: alpha-olefin sulfonates; hydroxyethylcellulose; and combinations thereof. ### Claim 5 (depends on 1) The method according to claim 1, where the exothermic reaction component comprises NH4Cl and NaNO2. ### Claim 6 (depends on 1) The method according to claim 1, where the exothermic reaction component comprises an ammonium containing compound selected from the group consisting of: ammonium chloride; ammonium bromide; ammonium nitrate; ammonium sulfate; ammonium carbonate; ammonium hydroxide; and mixtures thereof. ### Claim 7 (depends on 6) The method according to claim 6, where the exothermic reaction component comprises a nitrite containing compound selected from the group consisting of: sodium nitrite; potassium nitrite; and mixtures thereof. ### Claim 8 (depends on 1) The method according to claim 1, where the exothermic reaction component comprises at least one ammonium containing compound at about 3 molar (M) concentration and at least one nitrite containing compound at about 3 molar (M) concentration. ### Claim 9 (depends on 1) The method according to claim 1, where the viscous fluid component comprises asphaltenes and corrosion products in the wellbore. ### Claim 10 (depends on 9) The method according to claim 9, where the corrosion products are selected from the group consisting of: iron oxides, iron sulfides, sodium chloride, calcium carbonate, silica, and mixtures thereof. ### Claim 11 (depends on 1) The method according to claim 1, where reducing viscosity of the viscous fluid component to create the reduced viscosity material increases injectivity of the wellbore. ### Claim 12 (depends on 1) The method according to claim 1, further comprising the step of injecting an oxidizer into the wellbore to increase temperature of the wellbore or reservoir before the step of injecting the exothermic reaction component into the wellbore. ### Claim 13 (depends on 12) The method according to claim 12, where the oxidizer comprises at least one compound selected from the group consisting of: tertiary amines; organic esters; and transition metal salts. ### Claim 14 (depends on 1) The method according to claim 1, further comprising the step of injecting an oxidizer into the wellbore as a breaker after the step of injecting the exothermic reaction component into the wellbore. ### Claim 15 (depends on 14) The method according to claim 14, where the oxidizer comprises at least one compound selected from the group consisting of: tertiary amines; organic esters; and transition metal salts. ### Claim 16 (depends on 1) The method according to claim 1, where the heat reduces a viscosity of the viscous fluid component to create the reduced viscosity material in less than about 1 minute. ### Claim 17 (depends on 1) The method according to claim 1, further comprising the step of preparing an acid precursor, the acid precursor present at a low concentration not greater than about 5% by volume of the cleanup fluid to trigger the exothermic reaction component, in addition to or alternative to heat in the wellbore or reservoir. ### Claim 18 (depends on 17) The method according to claim 17, where the acid precursor comprises at least one component selected form the group consisting of: triacetin; methyl acetate; hydrochloric acid; acetic acid; and mixtures thereof.