08-07-2021 дата публикации
Номер: US20210207019A1
A method of removing iron-containing scale from a wellbore, pipe, or metal-containing surface involving contacting the iron-containing scale with a biodegradable descaler solution of water, hydrochloric acid, formic acid, citric acid, a corrosion inhibitor, a corrosion inhibitor intensifier, and a surfactant. The method is performed at a pressure of 14 to 400 psi and a temperature of 100 to 150° C. The method removes iron-containing scale made of iron sulfide, iron carbonate, iron oxyhydroxide, and calcium carbonate. The method meets industry standard steel corrosion rates of less than 0.049 lb/ftper day. Also disclosed is a biodegradable descaler solution of water, hydrochloric acid, formic acid, citric acid, a corrosion inhibitor, a corrosion inhibitor intensifier, and a surfactant that meets OECD 301B thresholds for ready biodegradability. 1: A method for removing an iron-containing scale from a wellbore , pipe , or other metal-containing surface , the method comprising: 55.75 to 80.49 wt % of water,', '16.0 to 22.5 wt % of hydrochloric acid,', '0.75 to 7.5 wt % of formic acid,', '0.75 to 7.5 wt % of citric acid,', '1.0 to 3.0 wt % of a corrosion inhibitor,', '1.0 to 3.0 wt % of a corrosion inhibitor intensifier, and', '0.01 to 0.75 wt % of a surfactant, each based on a total weight of the biodegradable descaler solution;, 'contacting the iron-containing scale with a biodegradable descaler solution comprising'}wherein the biodegradable descaler solution is contacted with the iron-containing scale at a pressure of 14 to 400 psi, andwherein the iron-containing scale has a solubility of 75 to 95 g/L in the biodegradable descaler solution at a temperature of 100 to 150° C.2: The method of claim 1 , wherein the iron-containing scale comprises iron sulfide claim 1 , iron carbonate claim 1 , iron oxyhydroxide claim 1 , and calcium carbonate.3: The method of claim 2 , wherein the iron sulfide is one or more selected from the group consisting of pyrrhotite (FeS) claim 2 , ...
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