# US 10,246,630 B2 · Water solution, clean fracturing fluid and method for fracturing reservoir > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,246,630 B2 - Document ID: US10246630B2 - Status: Granted - Kind: B2 - Application number: 15/668,273 - Filed: 2017-08-03 - Published: 2018-11-22 - Granted: 2019-04-02 - Earliest claimed: 2017-05-19 - Assignees: China University of Petroleum (East China) - Applicants: China University of Petroleum(East China); Research Institute of Petroleum Exploration & Development - Inventors: Caili Dai; Mingwei Zhao; He Liu; Yining Wu; Guang Zhao; Yongpeng Sun; Xuepeng Wu - Web page: https://patentgrep.com/patent/US10246630B2 ## CPC - C09K 8/68: containing organic compounds - C07C 57/13: Dicarboxylic acids - C07C 57/145: Maleic acid - C07C 57/46: containing six-membered aromatic rings and other rings, e.g. cyclohexylphenylacetic acid - C07C 233/05: having the nitrogen atoms of the carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms - C07C 309/04: containing only one sulfo group - C09K 8/72: Eroding chemicals, e.g. acids - C09K 2208/26: Gel breakers other than bacteria or enzymes - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS ## Abstract The present invention relates to the fracturing field, and discloses a water solution, a clean fracturing fluid, and a method for fracturing reservoir. The water solution contains organic acid amidopropyl dimethylamine, an additive, and water, wherein, the additive is at least one of salicylate, cis-butenedioic acid, o-phthalic acid, dodecyl sulfonate, p-toluene sulfonate, and benzoate. The water solution has high carbon dioxide response performance, a clean fracturing fluid that contains the water solution has superior cyclic utilization performance, and the fracturing fluid can solve the problems of conventional fracturing fluids used in fracturing stimulation of oil and gas reservoirs, including incomplete gel breaking, severe damages to the reservoir, and severe contamination of flow-back fluid, etc. ## Claims ### Claim 1 A method for fracturing a reservoir, comprising: preparing an aqueous solution by: mixing an organic acid amidopropyl dimethylamine, an additive, and water, while stirring at a temperature of 30° C. to 50° C. for a time of 5 min to 20 min, wherein the additive is selected from the group consisting of salicylate, cis-butenedioic acid, o-phthalic acid, dodecyl sulfonate, p-toluene sulfonate, benzoate and combinations thereof, wherein a weight ratio of the organic acid amidopropyl dimethylamine and the additive is 8:1-12:1; introducing carbon dioxide at a rate of 0.1-0.5 L/min. into the aqueous solution for gelatinization, to form a clean fracturing fluid, wherein the carbon dioxide is introduced for a time sufficient render the clean fracturing fluid clear; injecting the clean fracturing fluid into a reservoir for fracturing; and introducing air, nitrogen, or an inert gas into the reservoir after the fracturing for gel breaking. ### Claim 2 (depends on 1) The method for fracturing a reservoir of claim 1, wherein the organic acid amidopropyl dimethylamine is selected from the group consisting of palmitamidopropyl dimethylamine, stearamidopropyl dimethylamine, oleamidopropyl dimethylamine, erucamidopropyl dimethylamine, behenamidopropyl dimethylamine, and combinations thereof. ### Claim 3 (depends on 1) The method for fracturing a reservoir of claim 1, wherein, based on the total weight of the aqueous solution, the amount of the organic acid amidopropyl dimethylamine is 1-6 wt %, the amount of the additive is 0.1-0.6 wt %, and the amount of water is 93.4-98.9 wt %. ### Claim 4 (depends on 1) The method for fracturing a reservoir of claim 1, wherein a weight ratio of the organic acid amidopropyl dimethylamine and the additive is 9.5:1-10.5:1. ### Claim 5 (depends on 1) The method for fracturing a reservoir of claim 1, wherein, when the reservoir temperature is lower than 50° C., the aqueous solution contains 1-2 wt % organic acid amidopropyl dimethylamine; when the reservoir temperature is 50-80° C., the aqueous solution contains 2-4 wt % organic acid amidopropyl dimethylamine; when the reservoir temperature is 80-95° C., the aqueous solution contains 4-6 wt % organic acid amidopropyl dimethylamine. ### Claim 6 (depends on 1) The method of claim 1, wherein the additive is selected from the group consisting of salicylate, cis-butenedioic acid, dodecyl sulfonate, p-toluene sulfonate, benzoate, and combinations thereof. ### Claim 7 A method of preparing an aqueous solution for use in fracturing a reservoir, the method comprising: mixing an organic acid amidopropyl dimethylamine, an additive, and water, while stirring at a temperature of 30° C. to 50° C. for a time of 5 min to 20 min; wherein, the additive is selected from the group consisting of salicylate, cis-butenedioic acid, o-phthalic acid, dodecyl sulfonate, p-toluene sulfonate, benzoate and combinations thereof; wherein a weight ratio of the organic acid amidopropyl dimethylamine and the additive is 8:1-12:1. ### Claim 8 (depends on 7) The method of claim 7, wherein the organic acid amidopropyl dimethylamine is selected from the group consisting of palmitamidopropyl dimethylamine, stearamidopropyl dimethylamine, oleamidopropyl dimethylamine, erucamidopropyl dimethylamine, behenamidopropyl dimethylamine, and combinations thereof. ### Claim 9 (depends on 7) The method of claim 7, wherein, based on the total weight of the aqueous solution, the content of the organic acid amidopropyl dimethylamine is 1-6 wt %, the content of the additive is 0.1-0.6 wt %, and the content of water is 93.4-98.9 wt %. ### Claim 10 (depends on 7) The aqueous solution of claim 7, wherein a weight ratio of the organic acid amidopropyl dimethylamine and the additive is 9.5:1-10.5:1. ### Claim 11 A method of preparing a clean fracturing fluid, comprising: preparing an aqueous solution by: mixing an organic acid amidopropyl dimethylamine, an additive, and water, while stirring at a temperature of 30° C. to 50° C. for a time of 5 min to 20 min, wherein the additive is selected from the group consisting of salicylate, cis-butenedioic acid, o-phthalic acid, dodecyl sulfonate, p-toluene sulfonate, benzoate and combinations thereof, wherein a weight ratio of the organic acid amidopropyl dimethylamine and the additive is 8:1-12:1; introducing carbon dioxide at a rate of 0.1-0.5 L/min. into the aqueous solution for gelatinization, wherein the carbon dioxide is introduced for a time sufficient render the clean fracturing fluid clear. ### Claim 12 (depends on 11) The method of claim 11, wherein the organic acid amidopropyl dimethylamine is selected from the group consisting of palmitamidopropyl dimethylamine, stearamidopropyl dimethylamine, oleamidopropyl dimethylamine, erucamidopropyl dimethylamine, behenamidopropyl dimethylamine, and combinations thereof. ### Claim 13 (depends on 11) The method of claim 11, wherein, based on the total weight of the aqueous solution, the content of the organic acid amidopropyl dimethylamine is 1-6 wt %, the content of the additive is 0.1-0.6 wt %, and the content of water is 93.4-98.9 wt %. ### Claim 14 (depends on 11) The method of claim 11, wherein a weight ratio of the organic acid amidopropyl dimethylamine and the additive is 9.5:1-10.5:1.