METHOD FOR OBTAINING REAGENTS FOR DRILLING FLUIDS Russian patent published in 2016 - IPC C09K8/03 

FIELD: oil and gas industry.

SUBSTANCE: in method for obtaining reagents for drilling fluids by means of oxidation of lignosulphonates by hexavalent chromium compounds in acid medium, interaction of the formed chromelignosulphonate with ferrous sulphate and phosphorus-containing modifying agent, alkalizing by sodium hydroxide and drying, the phosphorus-containing modifying agent is represented by amino trimethylene phosphonic acid in quantity of 10-12 weight parts in regard to lignosulphonate, to the solution of sodium lignosulphonate bivalent ferrous sulphate is introduced in the form of dry powder and withhold within 1 hour at permanent stirring at temperature of 30-40°C. Then sodium bichromate is introduced in the form of aqueous solution and withhold within 1 hour at permanent stirring at temperature of 30-40°C. Then the phosphorus-containing modifying agent represented by amino trimethylene phosphonic acid is introduced in the form of aqueous solution and withhold within 1 hour at permanent stirring at temperature of 30-40°C. Further the mixture is neutralized by caustic soda up to pH 4-5 and dried until powder is obtained. The components are used with the following ratio on dry basis in weight parts: sodium lignosulphonate 100; bivalent ferrous sulphate 6.5-7.5; sodium bichromate 3-3.5; amino trimethylene phosphonic acid 10-12; caustic soda 0.14.

EFFECT: improved diluting properties of the reagent in mineralized drilling fluids, improved thermal stability of the reagent.

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