Abstract: Disclosed are heavy brine compositions containing zinc bromide and one or more soluble salts selected from the group consisting of calcium chloride and calcium bromide, preferably having a density in the range from about 14.2 to about 16.0 pounds per gallon, which have a low API fluid loss. Also disclosed is a method of formulating certain heavy brines in which hydroxyethyl cellulose functions as a fluid loss additive.

Abstract: A method of producing a well servicing fluid containing zinc bromide in which an activated hydroxyethyl cellulose is either admixed with a zinc bromide solution containing above about 30% by weight zinc bromide, or, in the alternative, is admixed with a non-zinc bromide containing solution to produce a viscosified solution which is then admixed with a zinc bromide containing solution.

Abstract: A polymeric composition useful in the thickening of aqueous brines comprising hydroxyethyl cellulose, a water miscible organic liquid and an aqueous liquid.

Abstract: Hydroxyethyl cellulose and a sequestrant are added to a heavy brine containing one or more salts selected from calcium chloride, calcium bromide, and zinc bromide to increase the viscosity of the brine. Preferably the brine contains zinc bromide, has a density in the range from about 14.2-19.2 pounds per gallon, and the sequestrant is a polyphosphonic acid or water soluble salt thereof.

Abstract: A method of activating hydroxyethyl cellulose (HEC) such that the HEC will hydrate in heavy brines having a density greater than about 13.5 pounds per gallon at ambient temperature, the activated HEC compositions so produced, and viscous well servicing compositions wherein an oleaginous liquid and a compatiblizing agent are admixed to form a viscous slurry, admixing therewith an aqueous solution of an inorganic salt which has an exothermic heat of solution, and thereafter admixing HEC therewith to form a viscous pourable composition.

Abstract: A method of producing a well servicing fluid containing zinc bromide in which an activated hydroxyethyl cellulose is either admixed with a zinc bromide solution containing above about 30% by weight zinc bromide, or, in the alternative, is admixed with a non-zinc bromide containing solution to produce a viscosified solution which is then admixed with a zinc bromide containing solution.

Abstract: Hydroxyethyl cellulose and a sequestrant are added to a heavy brine containing one or more salts selected from calcium chloride, calcium bromide, and zinc bromide to increase the viscosity of the brine. Preferably the brine contains zinc bromide, has a density in the range from about 14.2-19.2 pounds per gallon, and the sequestrant is a polyphosphonic acid or water soluble salt thereof.

Abstract: Polymeric compositions for, and methods of, increasing the viscosity of aqueous brine well servicing fluids comprising adding to the brine a composition containing hydroxyethyl cellulose, a solid organic activating agent for the hydroxyethyl cellulose, and a solvent for the activating agent which also functions as a suspending medium or carrier for the hydroxyethyl cellulose.

Abstract: A polymer composition for use in aqueous mediums comprising a hydrophilic polymer, a water miscible polar organic liquid which acts as a solvating agent for the hydrophilic polymer, the solvating agent being of a type which forms a semi-solid to viscous mixture with the hydrophilic polymer under certain conditions, and a diluting agent which is a non-solvating agent for the hydrophilic polymer. The polymer compositions can be added to aqueous mediums, particularly heavy brines, to produce well servicing fluids.

Abstract: A thickened brine solution useful as a well servicing fluid is prepared, said solution consisting essentially of water, at least 20% by weight zinc bromide, calcium bromide, and a viscosifying amount of hydroxyethyl cellulose.

Abstract: A polymeric composition useful in the thickening of aqueous brines comprising hydroxyethyl cellulose, a water miscible organic liquid and an aqueous liquid.

Abstract: A hydrophilic polymer composition for use in thickening aqueous mediums comprising hydroxyethyl cellulose, a water miscible polar organic liquid which acts as solvating agent for the hydroxyethyl cellulose, the solvating agent being of a type which forms a semi-solid to viscous mixture with the hydroxyethyl cellulose under certain conditions. The polymeric composition alone, or in admixture with a diluting agent which is a non-solvating agent for the hydroxyethyl cellulose, can be added to aqueous mediums, particularly heavy brines, to produce well servicing fluids.