METHODS AND COMPOSITIONS FOR INCREASING VISCOSITY OF HEAVY WATER BRINE Russian patent published in 2015 - IPC C09K8/42 

FIELD: chemistry.

SUBSTANCE: invention relates to compositions for increasing viscosity of heavy brine systems. Method of increasing viscosity of brine systems, used in underground repair of wells, includes: a) obtaining brine system, including hydrated polysaccharide and, at least, one polyvalent salt, where density of brine system constitutes more than approximately 1.2 g/cm³ and pH constitutes less than approximately 7, at least, one polyvalent salt is present in amount from approximately 5 wt % to approximately 90 wt % of the total weigh of brine system and b) addition of effective quantity of alkaline preparation, increasing viscosity of brine system, where alkaline preparation is selected from the group, consisting of amines, glycerophosphates of alkali metals, orthophosphates of alkali metals, hydroxides of alkali metals, carbonates, alkanolamines, silicates, citrates, phosphates, buffer solutions of thereof and their mixtures. In accordance with the second version method of increasing viscosity of brine systems, used in underwater repair of wells, includes: a) obtaining water brine system, including, at least, one polyvalent salt, where density of brine system constitutes more than approximately 1.2 g/cm³ and pH constitutes less than approximately 7, at least, one polyvalent salt is present in amount from approximately 5 wt % to approximately 90 wt % of the total weigh of brine system; b) addition of polysaccharide; c) addition of effective quantity of acidic buffer preparation into brine system to reduce pH of hydrochloric system, so that polysaccharide becomes able to be considerably hydrated in brine system, and d) addition of effective quantity of alkaline preparation, increasing viscosity of brine system, where alkaline preparation is selected from the group, consisting of amine, glycerophpsphates of alkali metals, orthophosphates of alkali metals, hydroxides of alkali metals, carbonates, alkanilamines, silicates, citrates, phosphates, buffer solutions of thereof and their mixtures. In accordance with other version method of obtaining brine system with increased viscosity, used in underground repair of wells, includes: a) addition of polysaccharide to water hydrochloric solution, including: (i) at least, one polyvalent water-soluble salt, present in amount from approximately 5 wt % to approximately 90 wt % of the total weight of brine system; (ii) density between 1.2 g/cm³ and 2.4 g/cm³ and (iii) pH value, smaller than approximately 7, due to which polysaccharide is capable of considerable hydration in hydrochloric solution, and b) addition of alkali preparation to increase pH of hydrochloric solution, with increase of brine system viscosity, where alkaline preparation is selected from the group, consisting of amines, glycerophosphates of alkali metals, orthophosphates of alkali metals, hydroxides of alkali metals, carbonates, alkanilamines, silicates, citrates, phoaphates, buffer solutions of thereof and their mixtures. In accordance with other version method of obtaining brine system with increased viscosity, used in underground repair of wells, includes: a) addition of polysaccharide to water hydrochloric solution, including: (i) at least, one polyvalent salt, present in amount from approximately 5 wt % to approximately 90 wt % of the total weight of brine system; (ii) density between 1.2 g/cm³ and 2.4 g/cm³; b) addition of affective quantity of acid to hydrochloric solution so that polysaccharide is capable of considerable hydration in hydrochloric solution and c) addition of alkaline preparation to increase pH of hydrochloric solution to value higher than 6, increasing viscosity of brine system, where alkaline preparation is selected from the group, consisting of amines, glycerophpsphates of alkaline metals, orthophosphates of alkali metals, hydroxides of alkali metals, carbonates, alkanolamines, silicates, citrates, phosphates, buffer solutions of thereof and their mixtures. Invention is developed in dependent items of the formula.

EFFECT: increased efficiency without application of cross-linking agents.

13 cl, 6 ex, 6 tbl