METHODS AND COMPOSITIONS FOR VISCOSIFYING HEAVY AQUEOUS BRINES

摘要

A method for viscosifying brine systems utilized in oilfield applications comprising: a) preparing a heavy brine system comprising obtaining an aqueous brine system comprising a hydrated polysaccharide and at least one multivalent salt, wherein the density of the aqueous brine system is greater than about 10 pounds per gallon (ppg), and adding an effective amount of an alkaline agent, thereby increasing the viscosity of the brine system. Also disclosed are methods for viscosifying brine systems utilized in well servicing applications comprising obtaining an aqueous brine solution comprising at least one multivalent salt, wherein the density of the aqueous brine system is greater than about 10 pounds per gallon (ppg); adding a polysaccharide; adding an effective amount of an acid buffering agent to the brine system to lower the pH of the brine system, whereby the polysaccharide is capable of substantially hydrating into the brine system; and adding an effective amount of an alkaline agent, thereby substantially increasing the viscosity of the brine system.