Patent attributes
A method of treating a subterranean formation with a xanthan-viscosified cesium formate brine wherein the pH and/or another characteristic selected from density, xanthan loading, sodium formate loading, potassium formate loading and combinations thereof are modified to delay solid hydrogel formation and maintain pumpability. Also disclosed is a method of delaying onset of solid hydrogel formation, in a gel comprising cesium formate brine viscosified with xanthan polymer, comprises introducing acid into the brine in an amount effective for a pH from 7 to 11, wherein the acid introduction is before, during or after xanthan viscosification and prior to hydrogel formation, wherein the hydrogel formation in the acidified gel occurs at a later time relative to the same gel at a natural pH.
